OFFSET
0,3
LINKS
Sergey Kitaev, Partially Ordered Generalized Patterns, Discrete Math. 298 (2005), no. 1-3, 212-229.
FORMULA
Let b(n) = A049774(n) = number of permutations avoiding a consecutive 123 pattern. Then a(n) = Sum_{i = 0..n-1} binomial(n-1,i) (a(n-1-i) + b(i) * a(n-1-i) - b(n-1-i)) for n >= 1 with a(0) = b(0) = 1. [See the recurrence for C_n on p. 220 of Kitaev (2005).] - Petros Hadjicostas, Oct 30 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 16 2019
EXTENSIONS
More terms from Petros Hadjicostas, Oct 30 2019
STATUS
approved