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A228671
Number of permutations of [n] having a shortest ascending run of length 4.
2
1, 0, 0, 0, 69, 250, 418, 658, 34649, 266267, 1369372, 5082045, 76637635, 876858377, 7147459470, 47396097511, 552146011437, 7418289082402, 82776784289657, 769968963165506, 9270154198456497, 136873296441831662, 1900983368776814542, 22997984983317347728
OFFSET
4,5
LINKS
Alois P. Heinz and Vaclav Kotesovec, Table of n, a(n) for n = 4..400 (first 100 terms from Alois P. Heinz)
FORMULA
a(n) ~ c * d^n * n!, where d = 0.50498188279961731119..., c = 0.223130847130100218... . - Vaclav Kotesovec, Sep 07 2014
EXAMPLE
T(4) = 1: 1234.
T(8) = 69: 12354678, 12364578, ..., 46781235, 56781234.
CROSSREFS
Column k=4 of A064315.
Sequence in context: A283053 A249899 A009434 * A115920 A183447 A296126
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 29 2013
STATUS
approved