I wish to use a formula like the below:

=B13

This is an example, However, instead of the row number being fixed (in this case, 13), I want to be able to specify the row number based on a simple formula. So it might look something like this (pseudocode)

=B(A3+1)

So, the row number would be the value in A3 added to one. Can anyone help me with the code. Thanks
Im not sure if my question is that clear based on the answs so far. I want the row part of the cell reference to be a function of two other numbers. So where the row number of B1 is 1, I want the 1 part to be a function of a number added in one cell to the integer one.
I still dont think im getting through to anyone, altho thx everyone so far with your efforts. Its difficult to explain. I want the row number part of the cell reference (i.e. where with B3 the row number is 3 for example) to be the value in A3 added to 1. I know the formula is A3+1 but I cant put =B(A3+1) it doesnt work!