login
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
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: A139927 A337197 A357365 * A044157 A044538 A297226
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 29 2013
STATUS
approved