a(n) = n^4 + 3*n^3 - 3*n.

Terms

a(0) =1a(1) =34a(2) =153a(3) =436a(4) =985a(5) =1926a(6) =3409a(7) =5608a(8) =8721a(9) =12970a(10) =18601a(11) =25884a(12) =35113a(13) =46606a(14) =60705a(15) =77776a(16) =98209a(17) =122418a(18) =150841a(19) =183940a(20) =222201a(21) =266134a(22) =316273a(23) =373176a(24) =437425a(25) =509626a(26) =590409a(27) =680428a(28) =780361a(29) =890910