need help in constructing script

hi guys,
i need some suggestions/ideas in constructing a script for insert statement with below sample.

col1
101201
101202
101203
101204
101205

col2
al
al
al
al
al

col3
pl
pl
pl
pl
pl

i need to create an insert script where first four numbers(1012) in col1 is constant and the last two numbers are incrementing. your suggestions might help. thanks