## Number spiral diagonals

### Problem 28

Published on Friday, 11th October 2002, 06:00 pm; Solved by 72499; Difficulty rating: 5%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?