Number spiral diagonals
Problem 28
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
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?
from math import ceil
def run():
result = 0
num = 1
for i in range(1000):
num = num + (2 * (i + 1))
result += num
num = 1
for i in range(1001):
num = num + (4 * ceil(((i + 1) / 2)))
result += num
return int(result)