a(1) = 1, a(2) = -5; a(n) = -n^2 * Sum_{d|n, d < n} a(d) / d^2.

Terms

a(0) =1a(1) =-5a(2) =-9a(3) =4a(4) =-25a(5) =45a(6) =-49a(7) =0a(8) =0a(9) =125a(10) =-121a(11) =-36a(12) =-169a(13) =245a(14) =225a(15) =0a(16) =-289a(17) =0a(18) =-361a(19) =-100a(20) =441a(21) =605a(22) =-529a(23) =0a(24) =0a(25) =845a(26) =0a(27) =-196a(28) =-841a(29) =-1125