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 A290816 #29 Sep 25 2019 05:56:50 %S A290816 1,1,2,4,8,23,65,223,757,2824,10559,40994,160734,641420,2584587, %T A290816 10528305,43237978,178974779,745814185,3127246179,13185588894, %U A290816 55878618492,237905685582,1017225981255,4366536472758,18812074137141,81320795918871,352638701880227 %N A290816 Number of dissections of an n-gon into polygons with odd number of sides counted up to rotations and reflections. %H A290816 Andrew Howroyd, <a href="/A290816/b290816.txt">Table of n, a(n) for n = 3..200</a> %H A290816 E. Krasko, A. Omelchenko, <a href="http://www.combinatorics.org/ojs/index.php/eljc/article/view/v22i1p17">Brown's Theorem and its Application for Enumeration of Dissections and Planar Trees</a>, The Electronic Journal of Combinatorics, 22 (2015), #P1.17. %e A290816 For a(5) = 2 the dissections of a pentagon are: a dissection into 3 triangles; a dissection into one pentagon. %t A290816 (* See A295419 for DissectionsModDihedral *) %t A290816 DissectionsModDihedral[Mod[#, 2]& /@ Range[1, 31]] (* _Jean-François Alcover_, Sep 25 2019, after _Andrew Howroyd_ *) %o A290816 (PARI) \\ See A295419 for DissectionsModDihedral(). %o A290816 DissectionsModDihedral(apply(v->v%2, [1..25])) \\ _Andrew Howroyd_, Nov 22 2017 %Y A290816 Cf. A049124 (counted distinctly). %Y A290816 Cf. A001004, A290722, A295419. %K A290816 nonn %O A290816 3,3 %A A290816 _Evgeniy Krasko_, Sep 03 2017 %E A290816 Terms a(16) and beyond from _Andrew Howroyd_, Nov 22 2017