a(n) = Sum_{d|n, n/d=1 mod 4} d^3 - Sum_{d|n, n/d=3 mod 4} d^3.

Terms

a(0) =1a(1) =8a(2) =26a(3) =64a(4) =126a(5) =208a(6) =342a(7) =512a(8) =703a(9) =1008a(10) =1330a(11) =1664a(12) =2198a(13) =2736a(14) =3276a(15) =4096a(16) =4914a(17) =5624a(18) =6858a(19) =8064a(20) =8892a(21) =10640a(22) =12166a(23) =13312a(24) =15751a(25) =17584a(26) =18980a(27) =21888a(28) =24390a(29) =26208