G.f. A(x) satisfies A(x) = 1 + x/A(x)^2 * (1 - A(x) + A(x)^4).

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =7a(5) =29a(6) =61a(7) =256a(8) =596a(9) =2507a(10) =6247a(11) =26197a(12) =68652a(13) =286232a(14) =780508a(15) =3231060a(16) =9102590a(17) =37392935a(18) =108279767a(19) =441342883a(20) =1308552478a(21) =5292781266a(22) =16018989626a(23) =64315663716a(24) =198213843417a(25) =790252270626