a(n) = Sum_{k=0..n} ceiling(k^3/n).

Terms

a(0) =1a(1) =5a(2) =13a(3) =26a(4) =47a(5) =76a(6) =115a(7) =164a(8) =228a(9) =307a(10) =401a(11) =512a(12) =643a(13) =794a(14) =967a(15) =1162a(16) =1385a(17) =1632a(18) =1909a(19) =2214a(20) =2551a(21) =2920a(22) =3323a(23) =3760a(24) =4235a(25) =4751a(26) =5301a(27) =5900a(28) =6539a(29) =7222