G.f. A(x) satisfies A(x) = 1 + x/(1-9*x^3)^(1/3) * A( x/sqrt(1-9*x^3)^(1/3) ).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =10a(6) =19a(7) =49a(8) =154a(9) =415a(10) =1066a(11) =3322a(12) =10639a(13) =31279a(14) =96751a(15) =326908a(16) =1082065a(17) =3514285a(18) =12068659a(19) =42713311a(20) =148480885a(21) =523469791a(22) =1915394458a(23) =7043990266a(24) =25840482346a(25) =96913386589a(26) =370304345755