formula for deck of cards

OK. i have a deck of cards thing. numbers 1-52. this is a problem that i have to solve, yes if it were me i wouldnt use just numbers.

here's the numbers and what they need to come out to after the formula

x->y
5->13
19->10
52->2
34->6
13->11
8->13
23->9
40->5
3->1
11->13

here's the current formula. which works with some but not with all. i have to find a new formula or a way to do it that works on all. I suck at math hoping somebody much smarter than myself could help me out.

y = (14 - intval (( x ) / 4))

thank you

Can you be more specific about what you're trying to do?

It kind of looks like you're trying to convert 1-52 into 1-13 (value of the card without suit). I'm not sure I understand your mapping though. I would simply use y = ((x-1) % 13)+1. That will map 1-13 into 1-13, 14-26 into 1-13, 27-39 into 1-13, and 40-52 into 1-13.