=SUMPRODUCT((OFFSET(C4,0,0,10000,1)*(MOD(ROW(4:100 03),51)=4)))

"Mike Fogleman" wrote in message
news:XgDAd.39842$k25.6833@attbi_s53...
I want to sum C4 and each cell every 51st row down. C4+C55+C106+C157+....
etc.

Any ideas?
TIA Mike F