Number of cells of square lattice of edge 1/n inside quadrant of unit circle centered at 0.

Terms

a(0) =0a(1) =1a(2) =4a(3) =8a(4) =15a(5) =22a(6) =30a(7) =41a(8) =54a(9) =69a(10) =83a(11) =98a(12) =119a(13) =139a(14) =162a(15) =183a(16) =208a(17) =234a(18) =263a(19) =294a(20) =322a(21) =357a(22) =390a(23) =424a(24) =465a(25) =504a(26) =545a(27) =585a(28) =628a(29) =675