A246252 Number of permutations of [n] with exactly seven occurrences of the consecutive step pattern up, down, down.

2172534146099019, 336291324862551606, 31816048233798681066, 2348418329934108057072, 149140942861163014893024, 8573289075750149662810032, 460018114299281721089786796, 23509721961960146267578379640, 1160583084129910496820714859320

Offset

22,1

Links

Alois P. Heinz, Table of n, a(n) for n = 22..160

Formula

a(n) ~ c * (3*sqrt(3)/(2*Pi))^n * n! * n^7, where c = 0.0000001405593242634352116... = c0 * (c0-1)^7 / (3^7 * 7!), and c0 = (1 + exp(Pi/sqrt(3))) * sqrt(3) / (2*Pi). - Vaclav Kotesovec, Aug 26 2014

Crossrefs

Column k=7 of A242819.

Sequence in context: A216910 A309111 A047698 * A058445 A290540 A132910

Adjacent sequences: A246249 A246250 A246251 * A246253 A246254 A246255

Keyword

nonn

Author

Alois P. Heinz, Aug 20 2014

Status

approved