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

Terms

a(0) =1a(1) =2a(2) =0a(3) =4a(4) =-6a(5) =32a(6) =-88a(7) =376a(8) =-1376a(9) =5574a(10) =-22232a(11) =91548a(12) =-378736a(13) =1589304a(14) =-6719040a(15) =28647592a(16) =-122933470a(17) =530755764a(18) =-2303432600a(19) =10043949684a(20) =-43979901840a(21) =193309672224a(22) =-852599615912