106746domain: NAppears in sequencesNumber of permutations in S_{n+2} containing an increasing subsequence of length n.at n=21A217200Number of obtuse isosceles triangles on a centered hexagonal grid of size n.at n=11A241230G.f. A(x) satisfies A(x) = 1 + x*A(x)^3 / (1 + x*A(x)^3).at n=12A364864