Hand drawing possibilities for an uneven distribution

[BatsShadow]

I don't remember my basic college probabilty math, so I figured someone can explain this faster than I can figure out how to look up the answer in google.

I'm trying to calculate the total number of possible starting hands from a Magic the Gathering deck. The deck is 60 cards. There are 13 unique cards of various quantities (between 2 and 13 of each card). You need to draw 7, the order doesn't matter.

Can someone explain the basics of solving this? Thanks.