User blog comment:Milesprower2/MP2's Present Blog/@comment-5902099-20130508041719

8 + 5 = 13

(2 * 2) + (0 * 0) + (1 * 1) + (3 * 3) = 14

14 - 13 = 1

1 * 16 = 16

16 divided by 7 = 2 remainder 2

2 + 2 + 8 + 5 = 17

I'll go with 17.