a(n) = n^7*(n^4 + 1)/2.

Terms

a(0) =0a(1) =1a(2) =1088a(3) =89667a(4) =2105344a(5) =24453125a(6) =181538496a(7) =989075143a(8) =4296015872a(9) =15692921289a(10) =50005000000a(11) =142665578891a(12) =371522101248a(13) =896111571277