A228671 Number of permutations of [n] having a shortest ascending run of length 4.

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

Author

Alois P. Heinz, Aug 29 2013

Keywords

• nonn

Examples

			T(4) = 1: 1234.
T(8) = 69: 12354678, 12364578, ..., 46781235, 56781234.
		

Links

• Alois P. Heinz and Vaclav Kotesovec, Table of n, a(n) for n = 4..400 (first 100 terms from Alois P. Heinz)

Crossrefs

Column k=4 of A064315.

Formula

a(n) ~ c * d^n * n!, where d = 0.50498188279961731119..., c = 0.223130847130100218... . - Vaclav Kotesovec, Sep 07 2014