increment values in array by comparing with an another array

Hello there,

I've got an Array1 which contains values indexes more especfically. This array size can be variable from 1 to 20 elements.Then I want to create an Array2,  which will increment the value of all the elements by one each iteration except those elements or indexes stored in Array1.

I have tried almost everithing to do it, but I just cannot get my head around this. Any help?

THanks in advance