a(n) = 4*n^4 - 3*n^2.

Terms

a(0) =1a(1) =52a(2) =297a(3) =976a(4) =2425a(5) =5076a(6) =9457a(7) =16192a(8) =26001a(9) =39700a(10) =58201a(11) =82512a(12) =113737a(13) =153076a(14) =201825a(15) =261376a(16) =333217a(17) =418932a(18) =520201a(19) =638800a(20) =776601a(21) =935572a(22) =1117777a(23) =1325376a(24) =1560625a(25) =1825876a(26) =2123577a(27) =2456272a(28) =2826601a(29) =3237300