a(n) = Sum {0<d|n, n/d odd} d^11.

Terms

a(0) =1a(1) =2048a(2) =177148a(3) =4194304a(4) =48828126a(5) =362799104a(6) =1977326744a(7) =8589934592a(8) =31381236757a(9) =100000002048a(10) =285311670612a(11) =743012564992