diff --git a/internal/ceres/evaluator_test.cc b/internal/ceres/evaluator_test.cc
index 79006f7..a0b28ee 100644
--- a/internal/ceres/evaluator_test.cc
+++ b/internal/ceres/evaluator_test.cc
@@ -55,12 +55,14 @@
 using std::vector;
 
 // TODO(keir): Consider pushing this into a common test utils file.
-template<int kFactor, int kNumResiduals,
-         int N0 = 0, int N1 = 0, int N2 = 0, bool kSucceeds = true>
+template <int kFactor, int kNumResiduals, int... Ns>
 class ParameterIgnoringCostFunction
-    : public SizedCostFunction<kNumResiduals, N0, N1, N2> {
-  typedef SizedCostFunction<kNumResiduals, N0, N1, N2> Base;
+    : public SizedCostFunction<kNumResiduals, Ns...> {
+  typedef SizedCostFunction<kNumResiduals, Ns...> Base;
+
  public:
+  ParameterIgnoringCostFunction(bool succeeds = true) : succeeds_(succeeds) {}
+
   virtual bool Evaluate(double const* const* parameters,
                         double* residuals,
                         double** jacobians) const {
@@ -91,8 +93,11 @@
         }
       }
     }
-    return kSucceeds;
+    return succeeds_;
   }
+
+ private:
+  bool succeeds_;
 };
 
 struct EvaluatorTestOptions {
@@ -112,7 +117,7 @@
     : public ::testing::TestWithParam<EvaluatorTestOptions> {
   Evaluator* CreateEvaluator(Program* program) {
     // This program is straight from the ProblemImpl, and so has no index/offset
-    // yet; compute it here as required by the evalutor implementations.
+    // yet; compute it here as required by the evaluator implementations.
     program->SetParameterOffsetsAndIndex();
 
     if (VLOG_IS_ON(1)) {
@@ -457,12 +462,12 @@
   problem.AddParameterBlock(z,  4);
 
   // f(x, y) in R^2
-  problem.AddResidualBlock(new ParameterIgnoringCostFunction<1, 2, 2, 3>,
+ problem.AddResidualBlock(new ParameterIgnoringCostFunction<1, 2, 2, 3>,
                            NULL,
                            x, y);
 
   // g(x, z) in R^3
-  problem.AddResidualBlock(new ParameterIgnoringCostFunction<2, 3, 2, 4>,
+ problem.AddResidualBlock(new ParameterIgnoringCostFunction<2, 3, 2, 4>,
                            NULL,
                            x, z);
 
@@ -526,7 +531,7 @@
 TEST_P(EvaluatorTest, EvaluatorAbortsForResidualsThatFailToEvaluate) {
   // Switch the return value to failure.
   problem.AddResidualBlock(
-      new ParameterIgnoringCostFunction<20, 3, 2, 3, 4, false>, NULL, x, y, z);
+      new ParameterIgnoringCostFunction<20, 3, 2, 3, 4>(false), NULL, x, y, z);
 
   // The values are ignored.
   double state[9];
diff --git a/internal/ceres/line_search_preprocessor_test.cc b/internal/ceres/line_search_preprocessor_test.cc
index d0a866b..301509c 100644
--- a/internal/ceres/line_search_preprocessor_test.cc
+++ b/internal/ceres/line_search_preprocessor_test.cc
@@ -105,8 +105,8 @@
   EXPECT_TRUE(preprocessor.Preprocess(options, &problem, &pp));
 }
 
-template<int kNumResiduals, int N1 = 0, int N2 = 0, int N3 = 0>
-class DummyCostFunction : public SizedCostFunction<kNumResiduals, N1, N2, N3> {
+template <int kNumResiduals, int... Ns>
+class DummyCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
  public:
   bool Evaluate(double const* const* parameters,
                 double* residuals,
diff --git a/internal/ceres/parameter_block_ordering_test.cc b/internal/ceres/parameter_block_ordering_test.cc
index 339e73b..ba61be6 100644
--- a/internal/ceres/parameter_block_ordering_test.cc
+++ b/internal/ceres/parameter_block_ordering_test.cc
@@ -51,8 +51,8 @@
 typedef Graph<ParameterBlock*> HessianGraph;
 typedef std::unordered_set<ParameterBlock*> VertexSet;
 
-template <int M, int N1 = 0, int N2 = 0, int N3 = 0>
-class DummyCostFunction: public SizedCostFunction<M, N1, N2, N3> {
+template <int M, int... Ns>
+class DummyCostFunction : public SizedCostFunction<M, Ns...> {
   virtual bool Evaluate(double const* const* parameters,
                         double* residuals,
                         double** jacobians) const {
diff --git a/internal/ceres/program_test.cc b/internal/ceres/program_test.cc
index 52eaa40..01bf233 100644
--- a/internal/ceres/program_test.cc
+++ b/internal/ceres/program_test.cc
@@ -35,9 +35,10 @@
 #include <memory>
 #include <vector>
 
-#include "ceres/sized_cost_function.h"
+#include "ceres/internal/integer_sequence_algorithm.h"
 #include "ceres/problem_impl.h"
 #include "ceres/residual_block.h"
+#include "ceres/sized_cost_function.h"
 #include "ceres/triplet_sparse_matrix.h"
 #include "gtest/gtest.h"
 
@@ -62,22 +63,23 @@
 };
 
 // Templated base class for the CostFunction signatures.
-template <int kNumResiduals, int N0, int N1, int N2>
-class MockCostFunctionBase : public
-SizedCostFunction<kNumResiduals, N0, N1, N2> {
+template <int kNumResiduals, int... Ns>
+class MockCostFunctionBase : public SizedCostFunction<kNumResiduals, Ns...> {
  public:
   virtual bool Evaluate(double const* const* parameters,
                         double* residuals,
                         double** jacobians) const {
+    const int kNumParameters = Sum<integer_sequence<int, Ns...>>::Value;
+
     for (int i = 0; i < kNumResiduals; ++i) {
-      residuals[i] = kNumResiduals +  N0 + N1 + N2;
+      residuals[i] = kNumResiduals + kNumParameters;
     }
     return true;
   }
 };
 
-class UnaryCostFunction : public MockCostFunctionBase<2, 1, 0, 0> {};
-class BinaryCostFunction : public MockCostFunctionBase<2, 1, 1, 0> {};
+class UnaryCostFunction : public MockCostFunctionBase<2, 1> {};
+class BinaryCostFunction : public MockCostFunctionBase<2, 1, 1> {};
 class TernaryCostFunction : public MockCostFunctionBase<2, 1, 1, 1> {};
 
 TEST(Program, RemoveFixedBlocksNothingConstant) {
@@ -247,14 +249,14 @@
   problem.AddParameterBlock(y, 3);
   problem.AddParameterBlock(&z, 1);
 
-  problem.AddResidualBlock(new MockCostFunctionBase<2, 2, 0, 0>(), NULL, x);
-  problem.AddResidualBlock(new MockCostFunctionBase<3, 1, 2, 0>(), NULL, &z, x);
-  problem.AddResidualBlock(new MockCostFunctionBase<4, 1, 3, 0>(), NULL, &z, y);
-  problem.AddResidualBlock(new MockCostFunctionBase<5, 1, 3, 0>(), NULL, &z, y);
-  problem.AddResidualBlock(new MockCostFunctionBase<1, 2, 1, 0>(), NULL, x, &z);
-  problem.AddResidualBlock(new MockCostFunctionBase<2, 1, 3, 0>(), NULL, &z, y);
-  problem.AddResidualBlock(new MockCostFunctionBase<2, 2, 1, 0>(), NULL, x, &z);
-  problem.AddResidualBlock(new MockCostFunctionBase<1, 3, 0, 0>(), NULL, y);
+  problem.AddResidualBlock(new MockCostFunctionBase<2, 2>(), NULL, x);
+  problem.AddResidualBlock(new MockCostFunctionBase<3, 1, 2>(), NULL, &z, x);
+  problem.AddResidualBlock(new MockCostFunctionBase<4, 1, 3>(), NULL, &z, y);
+  problem.AddResidualBlock(new MockCostFunctionBase<5, 1, 3>(), NULL, &z, y);
+  problem.AddResidualBlock(new MockCostFunctionBase<1, 2, 1>(), NULL, x, &z);
+  problem.AddResidualBlock(new MockCostFunctionBase<2, 1, 3>(), NULL, &z, y);
+  problem.AddResidualBlock(new MockCostFunctionBase<2, 2, 1>(), NULL, x, &z);
+  problem.AddResidualBlock(new MockCostFunctionBase<1, 3>(), NULL, y);
 
   TripletSparseMatrix expected_block_sparse_jacobian(3, 8, 14);
   {
@@ -386,7 +388,7 @@
   double x[2];
   x[0] = 1.0;
   x[1] = std::numeric_limits<double>::quiet_NaN();
-  problem.AddResidualBlock(new MockCostFunctionBase<1, 2, 0, 0>(), NULL, x);
+  problem.AddResidualBlock(new MockCostFunctionBase<1, 2>(), NULL, x);
   string error;
   EXPECT_FALSE(problem.program().ParameterBlocksAreFinite(&error));
   EXPECT_NE(error.find("has at least one invalid value"),
@@ -396,7 +398,7 @@
 TEST(Program, InfeasibleParameterBlock) {
   ProblemImpl problem;
   double x[] = {0.0, 0.0};
-  problem.AddResidualBlock(new MockCostFunctionBase<1, 2, 0, 0>(), NULL, x);
+  problem.AddResidualBlock(new MockCostFunctionBase<1, 2>(), NULL, x);
   problem.SetParameterLowerBound(x, 0, 2.0);
   problem.SetParameterUpperBound(x, 0, 1.0);
   string error;
@@ -407,7 +409,7 @@
 TEST(Program, InfeasibleConstantParameterBlock) {
   ProblemImpl problem;
   double x[] = {0.0, 0.0};
-  problem.AddResidualBlock(new MockCostFunctionBase<1, 2, 0, 0>(), NULL, x);
+  problem.AddResidualBlock(new MockCostFunctionBase<1, 2>(), NULL, x);
   problem.SetParameterLowerBound(x, 0, 1.0);
   problem.SetParameterUpperBound(x, 0, 2.0);
   problem.SetParameterBlockConstant(x);
diff --git a/internal/ceres/reorder_program_test.cc b/internal/ceres/reorder_program_test.cc
index be548ef..cf3e9f6 100644
--- a/internal/ceres/reorder_program_test.cc
+++ b/internal/ceres/reorder_program_test.cc
@@ -45,9 +45,8 @@
 using std::vector;
 
 // Templated base class for the CostFunction signatures.
-template <int kNumResiduals, int N0, int N1, int N2>
-class MockCostFunctionBase : public
-SizedCostFunction<kNumResiduals, N0, N1, N2> {
+template <int kNumResiduals, int... Ns>
+class MockCostFunctionBase : public SizedCostFunction<kNumResiduals, Ns...> {
  public:
   virtual bool Evaluate(double const* const* parameters,
                         double* residuals,
@@ -57,8 +56,8 @@
   }
 };
 
-class UnaryCostFunction : public MockCostFunctionBase<2, 1, 0, 0> {};
-class BinaryCostFunction : public MockCostFunctionBase<2, 1, 1, 0> {};
+class UnaryCostFunction : public MockCostFunctionBase<2, 1> {};
+class BinaryCostFunction : public MockCostFunctionBase<2, 1, 1> {};
 class TernaryCostFunction : public MockCostFunctionBase<2, 1, 1, 1> {};
 
 TEST(_, ReorderResidualBlockNormalFunction) {
diff --git a/internal/ceres/solver_test.cc b/internal/ceres/solver_test.cc
index d11fef4..6acae0b 100644
--- a/internal/ceres/solver_test.cc
+++ b/internal/ceres/solver_test.cc
@@ -453,8 +453,8 @@
   EXPECT_TRUE(options.IsValid(&message));
 }
 
-template<int kNumResiduals, int N1 = 0, int N2 = 0, int N3 = 0>
-class DummyCostFunction : public SizedCostFunction<kNumResiduals, N1, N2, N3> {
+template <int kNumResiduals, int... Ns>
+class DummyCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
  public:
   bool Evaluate(double const* const* parameters,
                 double* residuals,
diff --git a/internal/ceres/trust_region_preprocessor_test.cc b/internal/ceres/trust_region_preprocessor_test.cc
index 0c91e21..47cc4fb 100644
--- a/internal/ceres/trust_region_preprocessor_test.cc
+++ b/internal/ceres/trust_region_preprocessor_test.cc
@@ -28,6 +28,7 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
+#include <array>
 #include <map>
 
 #include "ceres/ordered_groups.h"
@@ -113,8 +114,8 @@
   EXPECT_TRUE(preprocessor.Preprocess(options, &problem, &pp));
 }
 
-template<int kNumResiduals, int N1 = 0, int N2 = 0, int N3 = 0>
-class DummyCostFunction : public SizedCostFunction<kNumResiduals, N1, N2, N3> {
+template <int kNumResiduals, int... Ns>
+class DummyCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
  public:
   bool Evaluate(double const* const* parameters,
                 double* residuals,
@@ -127,30 +128,13 @@
       return true;
     }
 
-    if (jacobians[0] != NULL) {
-      MatrixRef j(jacobians[0], kNumResiduals, N1);
-      j.setOnes();
-      j *= kNumResiduals * N1;
-    }
-
-    if (N2 == 0) {
-      return true;
-    }
-
-    if (jacobians[1] != NULL) {
-      MatrixRef j(jacobians[1], kNumResiduals, N2);
-      j.setOnes();
-      j *= kNumResiduals * N2;
-    }
-
-    if (N3 == 0) {
-      return true;
-    }
-
-    if (jacobians[2] != NULL) {
-      MatrixRef j(jacobians[2], kNumResiduals, N3);
-      j.setOnes();
-      j *= kNumResiduals * N3;
+    std::array<int, sizeof...(Ns)> N{Ns...};
+    for (size_t i = 0; i < N.size(); ++i) {
+      if (jacobians[i] != NULL) {
+        MatrixRef j(jacobians[i], kNumResiduals, N[i]);
+        j.setOnes();
+        j *= kNumResiduals * N[i];
+      }
     }
 
     return true;