a(n) = A000203(n)^2 - A001157(n) - 2n = sigma(n)^2 - sigma_2(n) - 2n.

Terms

a(0) =-2a(1) =0a(2) =0a(3) =20a(4) =0a(5) =82a(6) =0a(7) =124a(8) =60a(9) =174a(10) =0a(11) =550a(12) =0a(13) =298a(14) =286a(15) =588a(16) =0a(17) =1030a(18) =0a(19) =1178a(20) =482a(21) =642a(22) =0a(23) =2702a(24) =260a(25) =862a(26) =726a(27) =2030a(28) =0a(29) =3824