a(n) = (n*(n+1))^4.

Terms

a(0) =0a(1) =16a(2) =1296a(3) =20736a(4) =160000a(5) =810000a(6) =3111696a(7) =9834496a(8) =26873856a(9) =65610000a(10) =146410000a(11) =303595776a(12) =592240896a(13) =1097199376a(14) =1944810000a(15) =3317760000a(16) =5473632256a(17) =8767700496a(18) =13680577296a(19) =20851360000a(20) =31116960000a(21) =45558341136a(22) =65554433296a(23) =92844527616a(24) =129600000000