G.f. A(x) satisfies 1 + 2*A(x) = Sum_{n>=0} (x + A(x)^n)^n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =6a(4) =22a(5) =64a(6) =238a(7) =813a(8) =3064a(9) =11276a(10) =43290a(11) =165781a(12) =647916a(13) =2541826a(14) =10085272a(15) =40216458a(16) =161537304a(17) =651906163a(18) =2644581776a(19) =10771863433a(20) =44052178217a(21) =180771472434a(22) =744215912074