G.f. A(x) satisfies both A(-x)*A(x) = A(x^2) and xA(x)^2 = B(xA(x^2)) where B(x) = x*(1+x)/(1-x).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =4a(6) =5a(7) =10a(8) =12a(9) =23a(10) =31a(11) =58a(12) =79a(13) =145a(14) =207a(15) =374a(16) =540a(17) =964a(18) =1427a(19) =2522a(20) =3775a(21) =6626a(22) =10050a(23) =17532a(24) =26811a(25) =46561a(26) =71795a(27) =124188a(28) =192661a(29) =332228