A246254 Number of permutations of [n] with exactly nine occurrences of the consecutive step pattern up, down, down.

14708695606607601165843, 3541988733308075285027550, 503174667865819228904767230, 54504030281627517895808563770, 4983196403246326034913729334260, 405629500925435775383214597193020, 30367312487678851547450846684842845, 2136522202012396295876641497958908090

Offset: 28

Author

Alois P. Heinz, Aug 20 2014

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 28..160

Crossrefs

Column k=9 of A242819.

Formula

a(n) ~ c * (3*sqrt(3)/(2*Pi))^n * n! * n^9, where c = 0.0000000002026268159682390665... = c0 * (c0-1)^9 / (3^9 * 9!), and c0 = (1 + exp(Pi/sqrt(3))) * sqrt(3) / (2*Pi). - Vaclav Kotesovec, Aug 26 2014