G.f. A(x) satisfies: 1 - x*A(x) + x^2*A(x)^2 = Sum_{n>=0} (-x)^(n^2).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =12a(5) =36a(6) =112a(7) =360a(8) =1185a(9) =3970a(10) =13510a(11) =46564a(12) =162212a(13) =570256a(14) =2020512a(15) =7208015a(16) =25868510a(17) =93331707a(18) =338328434a(19) =1231650330a(20) =4500857724a(21) =16504664528a(22) =60713760264a(23) =223985185896a(24) =828514954047