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

Terms

a(0) =1a(1) =1a(2) =-26a(3) =1a(4) =126a(5) =-26a(6) =-342a(7) =1a(8) =703a(9) =126a(10) =-1330a(11) =-26a(12) =2198a(13) =-342a(14) =-3276a(15) =1a(16) =4914a(17) =703a(18) =-6858a(19) =126a(20) =8892a(21) =-1330a(22) =-12166a(23) =-26a(24) =15751a(25) =2198a(26) =-18980a(27) =-342a(28) =24390a(29) =-3276