G.f.: A(x) = Product_{n>=1} 1/(1 - 2^n*x^n)^(2/2^n).

Terms

a(0) =1a(1) =2a(2) =6a(3) =14a(4) =36a(5) =78a(6) =192a(7) =406a(8) =942a(9) =2018a(10) =4512a(11) =9450a(12) =21178a(13) =43950a(14) =95532a(15) =200398a(16) =431356a(17) =892518a(18) =1917572a(19) =3950614a(20) =8410230a(21) =17398466a(22) =36648980a(23) =75326754a(24) =159199004a(25) =326471706a(26) =683028924a(27) =1404145162a(28) =2930071798a(29) =5993625942