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 A259116 #33 Sep 15 2015 05:47:33 %S A259116 1,1,1,2,4,22,145,1875,31929,698183,18056523,538340256,18141423039, %T A259116 681939320185 %N A259116 Number of unrooted binary unordered tanglegrams of size n. %C A259116 Binary tanglegrams are pairs of bifurcating (degree 3 internal node) trees with a bijection between the leaves of the trees. Two tanglegrams are isomorphic if there is an isomorphism between the trees that preserves the bijection. Unrooted means that the tanglegram is composed of unrooted trees, and unordered means that two tanglegrams that differ by exchanging the trees and inverting the bijection are considered identical. %H A259116 S. C. Billey, M. Konvalinka, and F. A. Matsen IV, <a href="http://arxiv.org/abs/1507.04976">On the enumeration of tanglegrams and tangled chains</a>, arXiv:1507.04976 [math.CO], 2015. %H A259116 Ira M. Gessel, <a href="http://arxiv.org/abs/1509.03867">Counting tanglegrams with species</a>, arXiv:1509.03867 [math.CO], (13-September-2015) %H A259116 F. A. Matsen IV, S. C. Billey, D. A. Kas, and M. Konvalinka, <a href="http://arxiv.org/abs/1507.04784">Tanglegrams: a reduction tool for mathematical phylogenetics</a>, arXiv:1507.04784 [q-bio.PE], 2015. %H A259116 Frederick A. Matsen, <a href="https://github.com/matsengrp/tangle">Sage/GAP4 Code for generating tanglegrams</a> %Y A259116 Cf. A258620 (tanglegrams), A259114, A259115, A258486 (tangled chains), A258487, A258488, A258489. %K A259116 nonn,more %O A259116 1,4 %A A259116 _Frederick A. Matsen IV_, Jun 18 2015 %E A259116 More terms from _Ira M. Gessel_, Jul 19 2015