A202231 Number of permutations avoiding the consecutive pattern 45123.

1, 2, 6, 24, 119, 708, 4914, 38980, 347862, 3449292, 37622348, 447662376, 5770553184, 80106726784, 1191471740436, 18902847341664, 318639524995160, 5687162644422552, 107145206713313556, 2124840033683212648, 44245492380155416392, 965195327390976439656

Offset

1,2

Comments

a(n) is the number of permutations on [n] that avoid the consecutive pattern 45123. It is the same as the number of permutations which avoid 21543, 32154 or 34512.

Links

Ray Chandler, Table of n, a(n) for n = 1..40

A. Baxter, B. Nakamura, and D. Zeilberger. Automatic generation of theorems and proofs on enumerating consecutive Wilf-classes

Crossrefs

Cf. A177523, A202213-A202236.

Sequence in context: A202229 A202224 A202225 * A202228 A202230 A202232

Adjacent sequences: A202228 A202229 A202230 * A202232 A202233 A202234

Keyword

nonn

Author

Ray Chandler, Dec 15 2011

Status

approved