I want to create a numbering sequence with aplhabets and numbers both getting incremented.

I want to create two number sequences  for different objects-

1. Number sequence should be like
A00001 -A99999
then
B00000- B99999
Then
......
Z00001-Z99999

2. Number sequence should be like

A1

then
B2

then
C3
...
Z26

A sequence can be created for number instrumentation by using "exec wtpk.createSequence('sequence name', initial value, increment);" but what about alphabets and their concatenation with numbers?

Please give complete solution/approaches.