[Project Euler]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 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?

解答：

这个值需要做个简单的观察，右上角对角线是N的平方。所以就很简单

sum([4*i**2-6*i+6 for i in range(3, 103, 2)])+1

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