A246249 Number of permutations of [n] with exactly four occurrences of the consecutive step pattern up, down, down.

3052323, 186723630, 7683652710, 260901740745, 8002149813810, 231524173618290, 6486876741415365, 178899784802719290, 4910005699045578270, 135118835430805648215, 3748167756629344500390, 105205858082972481706290, 2996195115836815163207370

Offset

13,1

Links

Alois P. Heinz, Table of n, a(n) for n = 13..160

Formula

a(n) ~ c * (3*sqrt(3)/(2*Pi))^n * n! * n^4, where c = 0.000882722753946826148... = c0 * (c0-1)^4 / (3^4 * 4!), and c0 = (1 + exp(Pi/sqrt(3))) * sqrt(3) / (2*Pi). - Vaclav Kotesovec, Aug 26 2014

Crossrefs

Column k=4 of A242819.

Sequence in context: A184374 A205932 A281447 * A183696 A104963 A190462

Adjacent sequences: A246246 A246247 A246248 * A246250 A246251 A246252

Keyword

nonn

Author

Alois P. Heinz, Aug 20 2014

Status

approved