Range sum, multiplication

Hello Masters of the Universe of VBA Excel
I am starting to use VBA Macro and I search try to find a way to reduce this code that I need replicate many times.
All cells have integers. Cells(19,6) is a constant value.
How I can reduce this operations? Using a variable?
Please guide me with your expertise.

Thanks

Sheets("PxP").Cells(49, 4) = ((Cells(19, 6) + Cells(15, 4)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 5) = ((Cells(19, 6) + Cells(15, 5)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 6) = ((Cells(19, 6) + Cells(15, 6)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 7) = ((Cells(19, 6) + Cells(15, 7)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 8) = ((Cells(19, 6) + Cells(15, 8)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 9) = ((Cells(19, 6) + Cells(15, 9)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 10) = ((Cells(19, 6) + Cells(15, 10)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 11) = ((Cells(19, 6) + Cells(15, 11)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 12) = ((Cells(19, 6) + Cells(15, 12)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 13) = ((Cells(19, 6) + Cells(15, 13)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 14) = ((Cells(19, 6) + Cells(15, 14)) / 2) * Cells(15, 2)
Sheets("PxP").Cells(49, 15) = ((Cells(19, 6) + Cells(15, 15)) / 2) * Cells(15, 2)