a(n) is equal to the n-th order Taylor polynomial (centered at 0) of S(x)^n evaluated at x = 1, where S(x) = (1 - x - sqrt(1 - 6*x + x^2))/(2*x) is the o.g.f. of the Schröder numbers A006318.

A333090

a(n) is equal to the n-th order Taylor polynomial (centered at 0) of S(x)^n evaluated at x = 1, where S(x) = (1 - x - sqrt(1 - 6*x + x^2))/(2*x) is the o.g.f. of the Schröder numbers A006318.

Terms

    a(0) =1a(1) =3a(2) =21a(3) =183a(4) =1729a(5) =17003a(6) =171237a(7) =1752047a(8) =18130433a(9) =189218451a(10) =1987916021a(11) =20996253479a(12) =222730436161

External references