a(n) is the n-th order Taylor polynomial (centered at 0) of S(x)^(3*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.
A333092
a(n) is the n-th order Taylor polynomial (centered at 0) of S(x)^(3*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) =7a(2) =109a(3) =1951a(4) =36993a(5) =724007a(6) =14457421a(7) =292732671a(8) =5987886081a(9) =123440423047
External references
- oeis: A333092