Sum_{k=1..n-1} J(2*n,k)*k^2, where J(i,j) is the Jacobi symbol.

Terms

a(0) =0a(1) =1a(2) =1a(3) =-8a(4) =10a(5) =-24a(6) =17a(7) =84a(8) =25a(9) =24a(10) =115a(11) =-144a(12) =170a(13) =-224a(14) =98a(15) =32a(16) =244a(17) =654a(18) =803a(19) =-560a(20) =916a(21) =-616a(22) =-109a(23) =96a(24) =-152a(25) =312a(26) =913a(27) =-1120a(28) =2238a(29) =-1440