Hey guys, I need you help, creating a check digit.

I have a number: 012Q
Base sequence:
0123456789BCDFGHJKLMNPQRSTVWXYZ
I need to return the positions of each char:
0 1 2 22

Then something like: =MOD('0'+'1'+'2'+'22',31)+1
That will result in: 26

The end value I need returned is T as T is at position 26

Your help is much appreciated.