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%I #12 Oct 20 2014 17:15:15
%S 1,18,1566,354456,163932120,134973740880,180430456454640,
%T 366311352681348480
%N a(n) = number |fdw(P,(n))| of entangled P-words with s=3.
%C See Jenca and Sarkoci for the precise definition.
%H Gejza Jenca and Peter Sarkoci, <a href="http://arxiv.org/abs/1112.5782">Linear extensions and order-preserving poset partitions</a>, arXiv preprint arXiv:1112.5782, 2011
%F From Peter Bala, Sep 05 2012: (Start)
%F Conjectural e.g.f.: 2 - 1/A(x), where A(x) = sum {n = 0..inf} (3*n)!/6^n*x^n/n! is the e.g.f. for A014606 (also the o.g.f. for A025035).
%F If true, this leads to the recurrence equation: a(n) = (3*n)!/6^n - sum {k = 1..n-1} (3*k)!/6^k*binomial(n,k)*a(n-k) with a(1) = 1.
%F (End)
%Y Cf. A014606, A025035.
%K nonn
%O 1,2
%A _N. J. A. Sloane_, Apr 08 2012
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