a(n) = floor(n^3 / Pi).

Terms

a(0) =0a(1) =0a(2) =2a(3) =8a(4) =20a(5) =39a(6) =68a(7) =109a(8) =162a(9) =232a(10) =318a(11) =423a(12) =550a(13) =699a(14) =873a(15) =1074a(16) =1303a(17) =1563a(18) =1856a(19) =2183a(20) =2546a(21) =2947a(22) =3389a(23) =3872a(24) =4400a(25) =4973a(26) =5594a(27) =6265a(28) =6987a(29) =7763