Problem:

For each value of n from column C, we want to retrieve the nth value in row 1 (B1:I1), as well as the nth value in column A (A4:A11).

Solution:

To retrieve the nth value in the column, use the OFFSET function as shown in the following formula in column D:
=OFFSET($B$1,0,C4-1)

To retrieve the nth value in the row, use the OFFSET function as shown in the following formula in column E:
=OFFSET($A$4,C4-1,0)