a(n) = Sum_{i=1..n-1}(i^(n-2)) mod n^4.

Terms

a(0) =0a(1) =1a(2) =3a(3) =14a(4) =100a(5) =979a(6) =196a(7) =500a(8) =3834a(9) =1333a(10) =2178a(11) =1022a(12) =16731a(13) =12647a(14) =42420a(15) =23912a(16) =23409a(17) =26265a(18) =15162a(19) =79730a(20) =84441a(21) =21723a(22) =28566a(23) =160732a(24) =280625a(25) =329405a(26) =137295a(27) =569702a(28) =74849a(29) =71999