28 - Number spiral diagonals ✓.py

"""Starting with the number 1 and moving to the right in a clockwise direction a 5 by 5 spiral is formed as follows:

21 22 23 24 25
20  7  8  9 10
19  6  1  2 11
18  5  4  3 12
17 16 15 14 13

It can be verified that the sum of the numbers on the diagonals is 101.

What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral formed in the same way?"""
spirals = 1001
solution = 1
num =1
for i in range(2, spirals+1, 2):
  for j in range(4):
    num += i
    solution += num
print(solution)