a(n) is the sum over all floor(k^3/n), k=0 to n inclusive.

Terms

a(0) =1a(1) =4a(2) =11a(3) =24a(4) =43a(5) =71a(6) =109a(7) =160a(8) =222a(9) =298a(10) =391a(11) =502a(12) =631a(13) =781a(14) =953a(15) =1150a(16) =1369a(17) =1617a(18) =1891a(19) =2196a(20) =2531a(21) =2899a(22) =3301a(23) =3740a(24) =4215a(25) =4726a(26) =5283a(27) =5874a(28) =6511a(29) =7193