Expansion coefficients of the solution of a functional equation.

Terms

a(0) =1a(1) =2a(2) =2a(3) =2a(4) =4a(5) =12a(6) =32a(7) =72a(8) =148a(9) =318a(10) =772a(11) =2014a(12) =5216a(13) =13060a(14) =32168a(15) =80176a(16) =204714a(17) =531054a(18) =1380492a(19) =3574768a(20) =9247262a(21) =24023702a(22) =62819630a(23) =165074070a(24) =434726670a(25) =1145890266a(26) =3024348486a(27) =7999762500a(28) =21214170582a(29) =56378759128