A246248 Number of permutations of [n] with exactly three occurrences of the consecutive step pattern up, down, down.

11259, 443718, 12450834, 297195804, 6589314360, 141014406600, 2982538767870, 63210091744620, 1354523537530620, 29518995185712180, 656767731733672680, 14956075051814966040, 349170616179434073825, 8366057002343951876610, 205839505389444095064510

Offset

10,1

Links

Alois P. Heinz, Table of n, a(n) for n = 10..160

Formula

a(n) ~ c * (3*sqrt(3)/(2*Pi))^n * n! * n^3, where c = 0.01095971939528021798... = c0 * (c0-1)^3 / (3^3 * 3!), and c0 = (1 + exp(Pi/sqrt(3))) * sqrt(3) / (2*Pi). - Vaclav Kotesovec, Aug 26 2014

Crossrefs

Column k=3 of A242819.

Sequence in context: A135015 A104316 A237171 * A031630 A064870 A051520

Adjacent sequences: A246245 A246246 A246247 * A246249 A246250 A246251

Keyword

nonn

Author

Alois P. Heinz, Aug 20 2014

Status

approved