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

Terms

a(0) =0a(1) =0a(2) =27a(3) =0a(4) =0a(5) =27a(6) =343a(7) =0a(8) =27a(9) =0a(10) =1331a(11) =27a(12) =0a(13) =343a(14) =3402a(15) =0a(16) =0a(17) =27a(18) =6859a(19) =0a(20) =370a(21) =1331a(22) =12167a(23) =27a(24) =0a(25) =0a(26) =19710a(27) =343a(28) =0a(29) =3402