int j = i & ARRAY_MASK;
      tmp += IntMath.factorial(factorial[j]);
    }
    return tmp;
  }

  @Benchmark
  int binomial(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;
      tmp += IntMath.binomial(factorial[j], binomial[j]);
    }
    return tmp;
  }

  @Benchmark
  int isPrime(int reps) {
    int tmp = 0;

	a := newMatrix(n, n)
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			x1 := new(Rat).SetInt64(int64(i + j + 1))
			x2 := new(Rat).SetInt(new(Int).Binomial(int64(n+i), int64(n-j-1)))
			x3 := new(Rat).SetInt(new(Int).Binomial(int64(n+j), int64(n-i-1)))
			x4 := new(Rat).SetInt(new(Int).Binomial(int64(i+j), int64(i)))

			x1.Mul(x1, x2)
			x1.Mul(x1, x3)
			x1.Mul(x1, x4)
			x1.Mul(x1, x4)

			if (i+j)&1 != 0 {
				x1.Neg(x1)

      tmp += BigIntegerMath.factorial(factorials[j]).intValue();
    }
    return tmp;
  }

  @Benchmark
  int binomial(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & 0xffff;
      tmp += BigIntegerMath.binomial(factorials[j], binomials[j]).intValue();
    }
    return tmp;
  }

  }

  // Depends on the correctness of BigIntegerMath.binomial.
  public void testBinomial() {
    for (int n = 0; n <= 70; n++) {
      for (int k = 0; k <= n; k++) {
        BigInteger expectedBig = BigIntegerMath.binomial(n, k);
        long expectedLong = fitsInLong(expectedBig) ? expectedBig.longValue() : Long.MAX_VALUE;
        assertEquals(expectedLong, LongMath.binomial(n, k));
      }
    }
  }

  }

  // Depends on the correctness of BigIntegerMath.binomial.
  public void testBinomial() {
    for (int n = 0; n <= 70; n++) {
      for (int k = 0; k <= n; k++) {
        BigInteger expectedBig = BigIntegerMath.binomial(n, k);
        long expectedLong = fitsInLong(expectedBig) ? expectedBig.longValue() : Long.MAX_VALUE;
        assertEquals(expectedLong, LongMath.binomial(n, k));
      }
    }
  }

  }

  // Depends on the correctness of BigIntegerMath.binomial.
  public void testBinomial() {
    for (int n = 0; n <= 50; n++) {
      for (int k = 0; k <= n; k++) {
        BigInteger expectedBig = BigIntegerMath.binomial(n, k);
        int expectedInt = fitsInInt(expectedBig) ? expectedBig.intValue() : Integer.MAX_VALUE;
        assertEquals(expectedInt, IntMath.binomial(n, k));
      }
    }
  }

      int j = i & ARRAY_MASK;
      tmp += LongMath.factorial(factorialArguments[j]);
    }
    return tmp;
  }

  @Benchmark
  int binomial(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;
      tmp += LongMath.binomial(binomialArguments[j][0], binomialArguments[j][1]);
    }
    return tmp;
  }

  @Benchmark
  int isPrime(int reps) {
    int tmp = 0;

  static final Random RANDOM_SOURCE = new Random(314159265358979L);
  static final int MAX_EXPONENT = 100;

  /*
   * Duplicated from LongMath.
   * binomial(biggestBinomials[k], k) fits in a long, but not
   * binomial(biggestBinomials[k] + 1, k).
   */
  static final int[] biggestBinomials = {
    Integer.MAX_VALUE,
    Integer.MAX_VALUE,
    Integer.MAX_VALUE,
    3810779,
    121977,

  static final Random RANDOM_SOURCE = new Random(314159265358979L);
  static final int MAX_EXPONENT = 100;

  /*
   * Duplicated from LongMath.
   * binomial(biggestBinomials[k], k) fits in a long, but not
   * binomial(biggestBinomials[k] + 1, k).
   */
  static final int[] biggestBinomials = {
    Integer.MAX_VALUE,
    Integer.MAX_VALUE,
    Integer.MAX_VALUE,
    3810779,
    121977,

  };

  /**
   * Returns {@code n} choose {@code k}, also known as the binomial coefficient of {@code n} and
   * {@code k}, or {@link Integer#MAX_VALUE} if the result does not fit in an {@code int}.
   *
   * @throws IllegalArgumentException if {@code n < 0}, {@code k < 0} or {@code k > n}
   */
  public static int binomial(int n, int k) {
    checkNonNegative("n", n);
    checkNonNegative("k", k);