Ideas to modify graduation of row/columns in copied formulas with relative referencing to differ from their usual amount?

[appreciatethehelp]

As most of you know, when a formula is copied across or down in a spreadsheet, the columns/rows adjust proportionate to the distance that they are copied e.g. copy a formula from A1 to A2 and the row references in the formula (when relative) will increase by 1.

Anyone have any tips on how to modify this behaviour so that when the formulas are copied the references change by a different amount, other than by merely changing the distance that they are copied?

For example let’s say there’s a spreadsheet with two columns- A and B.
In A1 the formula is =B1. If I copy it down one row, is there any way to get it to reference, say B3, rather than B2, without having to copy it down the two rows normally required?
Perhaps using the row function or something?

As always, thanks in advance.

[anon73440385]

What is the pattern?

A1: =B1, A2: =B3 is not sufficient to recognize the pattern, but only to guess the most simple one (which is ROW()*2-1 and =INDIRECT("B" & ROW()*2-1), =OFFSET($B$1;ROW()*2-2;0;1;1) or =INDEX(B:B;ROW()*2-1;1) would perform the required reference for "each second row of column B", which would be pattern {1,3,5,7,9,11,13,....}, k_n=k_n-1 + 2, k₀=1 )