This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A211311 #11 Oct 20 2014 17:15:15
%S A211311 1,68,34236,62758896,304863598320,3242854167461280,
%T A211311 66429116436728636640,2389384600126093124110080
%N A211311 a(n) = number |fdw(P,(n))| of entangled P-words with s=4.
%C A211311 See Jenca and Sarkoci for the precise definition.
%H A211311 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 A211311 From Peter Bala, Sep 05 2012: (Start)
%F A211311 Conjectural e.g.f.: 2 - 1/A(x), where A(x) = sum {n = 0..inf} (4*n)!/24^n*x^n/n! is the e.g.f. for A014608 (also the o.g.f. for A025036).
%F A211311 If true, this leads to the recurrence equation: a(n) = (4*n)!/24^n - sum {k = 1..n-1} (4*k)!/24^k*binomial(n,k)*a(n-k) with a(1) = 1.
%F A211311 (End)
%Y A211311 Cf. A014608, A025036.
%K A211311 nonn
%O A211311 1,2
%A A211311 _N. J. A. Sloane_, Apr 08 2012