A202216 Number of permutations avoiding the consecutive pattern 34521.

1, 2, 6, 24, 119, 708, 4914, 38976, 347775, 3447912, 37601586, 447346944, 5765604885, 80025786960, 1190085736014, 18877969022976, 318171464604945, 5677939605422880, 106955077375109430, 2120744934976978944, 44153462828412744975, 963040357207773472320

Offset: 1

Author

Ray Chandler, Dec 14 2011

Keywords

• nonn

Comments

a(n) is the number of permutations on [n] that avoid the consecutive pattern 34521. It is the same as the number of permutations which avoid 12453, 31245, 35421, 54213, 12543, 32145 or 54123.

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.