# Sum Every nth Row In Calc [closed]

I need to sum every nth row in LO 6.0 Calc. I am trying to find out how many rows of a name and address list are populated so I can build a print range.

The column that is being used to test two rows for the presence of data contains a formula such as =IF(A12>0,1,0) to give a 0 for an empty row or 1 for a populated row. Underneath those two rows is a formula such as =IF(SUM(F11:F13)>0,1,0) to see if either row is populated.

I can tell if a group of rows contains data, but I need to know how many of these groups there are.