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 A005507 M1622 #33 Feb 23 2021 10:07:10 %S A005507 2,6,18,52,166,524,1722,5664,19072,64408,220676,758864,2634734, %T A005507 9180872,32208376,113371636,401067522,1423073892,5068961452, %U A005507 18103192360,64853607912,232872927444,838311889890,3023961593292,10931277735230,39586258360246,143617299291242 %N A005507 Number of unrooted triangulations with reflection symmetry of a hexagon with n internal nodes. %C A005507 These are also called [n,3]-triangulations. %D A005507 C. F. Earl and L. J. March, Architectural applications of graph theory, pp. 327-355 of R. J. Wilson and L. W. Beineke, editors, Applications of Graph Theory. Academic Press, NY, 1979. %D A005507 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A005507 Andrew Howroyd, <a href="/A005507/b005507.txt">Table of n, a(n) for n = 0..200</a> %H A005507 C. F. Earl and L. J. March, <a href="/A005500/a005500_1.pdf">Architectural applications of graph theory</a>, pp. 327-355 of R. J. Wilson and L. W. Beineke, editors, Applications of Graph Theory. Academic Press, NY, 1979. (Annotated scanned copy) %H A005507 C. F. Earl & N. J. A. Sloane, <a href="/A005500/a005500.pdf">Correspondence, 1980-1981</a> %F A005507 a(n) = 2 * A005502(n) - A005495(n) (based on _Max Alekseyev_'s formula, cf. A005500 and A005501). %Y A005507 Column k=3 of the array in A169809. %Y A005507 Cf. A005495, A005502. %K A005507 nonn %O A005507 0,1 %A A005507 _N. J. A. Sloane_ %E A005507 a(5)-a(10) from _Altug Alkan_ and _Manfred Scheucher_, Mar 08 2018 %E A005507 Name clarified and terms a(11) and beyond from _Andrew Howroyd_, Feb 21 2021