a(n) = (n^2 + 2*(Sum_{j = 1..n} j^n)) (mod n^3).

Terms

a(0) =0a(1) =6a(2) =0a(3) =20a(4) =0a(5) =26a(6) =0a(7) =200a(8) =567a(9) =950a(10) =0a(11) =1276a(12) =0a(13) =2058a(14) =2475a(15) =784a(16) =0a(17) =3750a(18) =0a(19) =4932a(20) =6615a(21) =4114a(22) =0a(23) =2264a(24) =13125a(25) =3718a(26) =13851a(27) =588a(28) =0a(29) =8050