@@ -0,0 +1,668 @@
+%22%22%22 Project Euler problem #28. %22%22%22%0A%0A%0Adef problem():%0A    %22%22%22 Solve the problem.%0A%0A    Starting with the number 1 and moving to the right in a clockwise direction%0A    a 5 by 5 spiral is formed as follows:%0A%0A        21 22 23 24 25%0A        20  7  8  9 10%0A        19  6  1  2 11%0A        18  5  4  3 12%0A        17 16 15 14 13%0A%0A    It can be verified that the sum of the numbers on the diagonals is 101.%0A%0A    What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral%0A    formed in the same way?%0A%0A    Answer: 669171001%0A%0A    %22%22%22%0A    size = 1001%0A    return sum(n**2 * 4 - 6 * n + 6 for n in range(3, size+1, 2)) + 1%0A%0A%0Aif __name__ == '__main__':%0A    print problem()%0A

Solve 28.