27959880

Appears in sequences

• a(n) is the number of permutations of [1..n] that avoid the consecutive pattern 1324 (equally, the permutations that avoid 4231).at n=11A113228
• Number T(n,k) of permutations of [n] with exactly k (possibly overlapping) occurrences of the consecutive pattern 1324; triangle T(n,k), n>=0, 0<=k<=max(0,floor(n/2-1)), read by rows.at n=27A264173