A246254 - OEIS

%I #10 Aug 26 2014 17:06:12

%S 14708695606607601165843,3541988733308075285027550,

%T 503174667865819228904767230,54504030281627517895808563770,

%U 4983196403246326034913729334260,405629500925435775383214597193020,30367312487678851547450846684842845,2136522202012396295876641497958908090

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

%H Alois P. Heinz, <a href="/A246254/b246254.txt">Table of n, a(n) for n = 28..160</a>

%F 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

%Y Column k=9 of A242819.

%K nonn

%O 28,1

%A _Alois P. Heinz_, Aug 20 2014