long unused = simpleBinomial(LongMath.biggestSimpleBinomials[k], k); // mustn't throw
      if (LongMath.biggestSimpleBinomials[k] < Integer.MAX_VALUE) {
        // unless all n are fair game with this k
        assertThrows(
            ArithmeticException.class,
            () -> simpleBinomial(LongMath.biggestSimpleBinomials[k] + 1, k));
      }
    }