So I'm tryna figure out how much farmland one water source block hydrates, and I think this structure is the best for this. This could apparently hydrate 2.278 x 10⁹⁷ (rounded to 3 significant figures) blocks of farmland when extended to y=0, which doesn't sound right to me. Can someone check if this structure is optimal and if my math is right?

fyi the formula i used is (3x3x4x2²)+(3x3x4x2³)...(3x3x4x2³¹⁶)+(3x3x12)