Excel: A function to replicate built-in change in relative references when copying formulas - vba

Question

I need a function that will do what Excel does automatically when you dreag a formula: change the referneces automatically.
For example:
In A1 I have "= A2 + A3"
If i copy this to say C3 it will have: "= C4 + C5"
I need to WRITE a formula in C3 that will produce this.
Any ideas? VBA solution is also welcome
CLARIFICATION:
In need this to be as general as possible.
Meaning A1 can contain ANY formula of any type, containing references to other cells.
for example: "= A2 + A3" or "= VLOOKUP(A2, $C$1:$E$7, 2, True)"
In need to move have this formula, whatever it is, copied to another cell (say C3), w/o the built in copy/paste, and have the references (that aren't set with $) change relatively.
I thought there might be a function to write in the destination file to do this.
I have tried writing an Eval function, and i managed to copy the formula from A1 and have it evaluated in C3, but the references would not change

Answer 1

This question lacks a bit of clarity, but I think this might be what you're after:
=SUM(OFFSET(C3,1,0,2))
This will sum the two cells directly below the given cell (in this case, cell C3). That is, it offsets C3 by 1 row, 0 columns, and grabs a height of 2 cells and then passes the result to the SUM function.

Answer 2

This VBA code would do what you are looking by setting the formula in the active cell:
ActiveCell.FormulaR1C1 = "=R[+1]C+R[+2]C"

Answer 3

You can use the Indirect() function using relative reference style.
For example, if you were in A1 and wanted to sum B1 & C1, it would look as follows:
A1: =INDIRECT("RC[1]",0)+INDIRECT("RC[2]",0)
That will change as you move the cell around to always sum the 2 cells to the left of the cell.
For your specific example (A1 = A2 + A3 || C3 = C4 + C5), it would be as follows:
=INDIRECT("R[1]C",0)+INDIRECT("R[2]C",0)
Hope that does the trick!!