Interlacing n^3/2 and n^2(n + 1)/2.

Terms

a(0) =1a(1) =4a(2) =18a(3) =32a(4) =75a(5) =108a(6) =196a(7) =256a(8) =405a(9) =500a(10) =726a(11) =864a(12) =1183a(13) =1372a(14) =1800a(15) =2048a(16) =2601a(17) =2916a(18) =3610a(19) =4000a(20) =4851a(21) =5324a(22) =6348a(23) =6912a(24) =8125a(25) =8788a(26) =10206a(27) =10976a(28) =12615a(29) =13500