Help please!

I need to check a range of cell if it has a value of 1 but the number of cell that i will be checking will base on a value of a cell.

scenario:

I will check a number of rows with value of 1 or greater than 0 starting cell B5, the number of rows to be check will be based on cell A1 which has a value of 15.
So it should check B5:B20 if any rows within it has a value of 1 or greater than 0.

the rows range will depend on the value of cell A1.


Thanks in Advance!