Cell format

Hi everyone!
I need to apply a custom format to my cells. The value i need to input are written in the format "00N000". The N is fixed, while the other numbers change. I can't use the general format, because i need to do some simple operation with those numbers. The final result must be a row with those values:
10N001
10N002
10N003
...
10N316
11N001
11N002

and so on. I hope the question is clear, i'm not the best at explaining myself in eng, and i hope there's a way to solve this too!

oh, wow, way easier than i though. I was missing the "", that's why i couldn't make it works. Thanks you so much and, even if it's offtopic, do you have any tips on how to do the same thing on access? because i need to import the excel table to access after that..