Number of solutions to 1^2 +- 3^2 +- 5^2 +- 7^2 +- ... +- (4*n-1)^2 = 0.

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =1a(5) =0a(6) =6a(7) =0a(8) =20a(9) =5a(10) =258a(11) =62a(12) =2510a(13) =914a(14) =24285a(15) =16403a(16) =263945a(17) =222240a(18) =3068971a(19) =3241157a(20) =35286928a(21) =46638022a(22) =426740187a(23) =650095127a(24) =5330192371a(25) =9185814630a(26) =67064945191a(27) =129902075662a(28) =864443143567