G.f. satisfies: A(x) = exp( Sum_{n>=1} (1+x)^n * A(x^n) * x^n/n ).

Terms

a(0) =1a(1) =1a(2) =3a(3) =8a(4) =23a(5) =67a(6) =202a(7) =622a(8) =1955a(9) =6248a(10) =20261a(11) =66484a(12) =220429a(13) =737260a(14) =2484734a(15) =8429714a(16) =28766001a(17) =98670291a(18) =340011308a(19) =1176505537a(20) =4086143638a(21) =14239716570a(22) =49776772808a(23) =174492148048a(24) =613266137776