A279292 - OEIS

%I #7 Dec 11 2016 11:49:38

%S 1,10,167,2064,28143,374166,5227491,75105984,1127851278,17625022976,

%T 287569327286,4891520843344,86749331150517,1602239541108282,

%U 30795187124606301,615261376037422992,12764913390565572333,274721686459213597782,6126847681304067647287

%N Number of permutations of [n] having exactly three (possibly overlapping) doubledescents.

%H Alois P. Heinz, <a href="/A279292/b279292.txt">Table of n, a(n) for n = 5..462</a>

%F a(n) ~ c * 3^(3*n/2) * n^(n+7/2) / (exp(n) * 2^n * Pi^n), where c = 0.0065517603957816327489026... . - _Vaclav Kotesovec_, Dec 11 2016

%Y Column k=3 of A162975.

%K nonn

%O 5,2

%A _Alois P. Heinz_, Dec 09 2016