209552

Appears in sequences

• The number of permutations that avoid the pattern 122'1', that is, out of four consecutive elements in a permutation we never have the situation that the first two elements form an ascent while the last two elements form a descent.at n=10A173385
• Number of fixed poly-[3.6.3.6]-tiles (holes allowed) with n cells (division into rhombi is significant).at n=11A197461