G.f. satisfies A(x) = (1 + 2*x*A(x)) * (1 + x*A(x)^2).
A215661
G.f. satisfies A(x) = (1 + 2*x*A(x)) * (1 + x*A(x)^2).
Terms
- a(0) =1a(1) =3a(2) =14a(3) =83a(4) =554a(5) =3966a(6) =29756a(7) =230915a(8) =1838162a(9) =14926346a(10) =123157572a(11) =1029590062a(12) =8702171620a(13) =74238432924a(14) =638408311800
External references
- oeis: A215661