a(n) = Sum_{d|n, d=3 mod 4} d^4.

Terms

a(0) =0a(1) =0a(2) =81a(3) =0a(4) =0a(5) =81a(6) =2401a(7) =0a(8) =81a(9) =0a(10) =14641a(11) =81a(12) =0a(13) =2401a(14) =50706a(15) =0a(16) =0a(17) =81a(18) =130321a(19) =0a(20) =2482a(21) =14641a(22) =279841a(23) =81a(24) =0a(25) =0a(26) =531522a(27) =2401a(28) =0a(29) =50706