Solution to problem 27 (brute-force)

- First, get all primes under 1000.
- Then, iterate on each primes giving us b
  (the larger coefficient).
- Within iteration, iterate further on primes
  lower than current prime b giving us a (the
  smaller coefficient) giving us calculations
  of nth triangle number where n = 168 (length
  of all primes under 1000).
- When we have our a and b, we need to test for
  4 types of calculations, where both are positive,
  both are negative, where a = negative and
  b = positive and a = positive and b = negative.
- Start at 0 and keep going until we get a prime result.