a(n) = (-1)^(n-1)*n*(4n^2-5)^2.

Terms

a(0) =1a(1) =-242a(2) =2883a(3) =-13924a(4) =45125a(5) =-115926a(6) =255367a(7) =-504008a(8) =915849a(9) =-1560250a(10) =2523851a(11) =-3912492a(12) =5853133a(13) =-8495774a(14) =12015375a(15) =-16613776a(16) =22521617a(17) =-30000258a(18) =39343699a(19) =-50880500