I am trying to create a macro which does an iterative process


I have a spreadsheet which performs a complicated series of calculations
based on a generic formula.

the 2 inputs that I have i would like to be changed are based in 2 cells and
I would like the value of the input (at the touch of a buttton) changed in an
iterative process ie a + 2; a+4 .... a+40, date+1day;
date+2day...date+20days. and then the result foudn in cell (x,y) I would
like paste into a matrix. a x b.

I presume that there is some standard coding which contains a looop function
which can perform this task,
Can anyone help?