#!/usr/bin/python3 from math import sqrt from timeit import default_timer from projecteuler import is_pentagonal def main(): start = default_timer() found = 0 n = 2 while not found: pn = n * (3 * n - 1) // 2 for m in range(1, n): pm = m * (3 * m - 1) // 2 if is_pentagonal(pn+pm) and is_pentagonal(pn-pm): found = 1 break n = n + 1 end = default_timer() print('Project Euler, Problem 44') print('Answer: {}'.format(pn-pm)) print('Elapsed time: {:.9f} seconds'.format(end - start)) if __name__ == '__main__': main()