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Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/6)] (6-way heap).
3

%I #11 May 28 2016 10:24:15

%S 1,1,1,2,6,24,120,720,2520,13440,90720,725760,6652800,68428800,

%T 444787200,4151347200,46702656000,597793996800,8468748288000,

%U 130660687872000,1241276534784000,16550353797120000,260668072304640000,4587758072561664000,87932029724098560000

%N Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/6)] (6-way heap).

%H Alois P. Heinz, <a href="/A178011/b178011.txt">Table of n, a(n) for n = 0..479</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/D-ary_heap">D-ary heap</a>

%Y Simple 2-way heap A056971.

%Y Column k=6 of A273693.

%K nonn

%O 0,4

%A _R. H. Hardin_, May 17 2010

%E a(0), a(21)-a(24) from _Alois P. Heinz_, May 27 2016