A246252 - OEIS

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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

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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