Q:

Calculate column number from alphabetic column reference in Excel

Here's a fun brain teaser.
Can you give me a mathematical equation to calculate the column number of a Microsoft Excel column, given the alphabetic column reference? Let X, Y, & Z represent the alphabetic sequence number, relative to the alphabet (A = 1, B = 2, etc.) 
I look forward to seeing your answers.

A:

It's not clear that your question is about the Mathematica software, but just in case, here's a stab at it:
Clear[converter]
converter[s_String] :=
 FromDigits[Characters[s], 26] /. Thread[CharacterRange["A", "Z"] -> Range[26]]

converter["AB"]
(* Out: 28 *)

