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A228670 Number of permutations of [n] having a shortest ascending run of length 3. 2
1, 0, 0, 19, 68, 110, 1679, 11941, 59470, 528974, 4907480, 36965659, 370685663, 4086527638, 40650345653, 458464525689, 5857242113368, 72283039099029, 938515852729074, 13416951764772945, 194738851363141390, 2909111655448399908, 46421744844240409407 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,4

LINKS

Alois P. Heinz and Vaclav Kotesovec, Table of n, a(n) for n = 3..480 (first 100 terms from Alois P. Heinz)

FORMULA

a(n) ~ c * d^n * n!, where d = 0.63140578989563018836245602310621356272419174622597338..., c = 0.2944330707154006599431970237808940992565854768253334... . - Vaclav Kotesovec, Sep 07 2014

EXAMPLE

a(3) = 1: 123.

a(6) = 19: 124356, 125346, 126345, 134256, 135246, 136245, 145236, 146235, 156234, 234156, 235146, 236145, 245136, 246135, 256134, 345126, 346125, 356124, 456123.

CROSSREFS

Column k=3 of A064315.

Sequence in context: A142404 A139927 A337197 * A044157 A044538 A297226

Adjacent sequences:  A228667 A228668 A228669 * A228671 A228672 A228673

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Aug 29 2013

STATUS

approved

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Last modified August 1 06:45 EDT 2021. Contains 346384 sequences. (Running on oeis4.)