SOLVED - Drag autofill whith increment in rows

You have Column A with 100000 values (thus in 100000 consecutive rows).
You want to auto-fill Column B so that you have in B1 the value A1, in B2 the value A101, in B3 the value A201, and so on.

I manually filled the first ones (B1=A1, B2=A101, B3=A201)
What would be the solution? If there is a function for that, could it be tailored so as to easily change the value of the increment, through an “increment value” cell, for example?

Thanks!