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 A005509 M3312 #22 Feb 23 2021 10:07:27 %S A005509 1,4,7,18,26,68,91,248,318,900,1122,3278,4004,12012,14443,44304,52598, %T A005509 164424,193154,613700,714476,2302344,2659582,8677072,9954860,32836180, %U A005509 37442160,124715430,141430680,475237500,536257995,1816267680,2040199590,6959878200 %N A005509 Number of unrooted triangulations with reflection symmetry of a disk with 2 internal nodes and n+3 nodes on the boundary. %D A005509 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 A005509 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A005509 Andrew Howroyd, <a href="/A005509/b005509.txt">Table of n, a(n) for n = 0..500</a> %H A005509 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 A005509 C. F. Earl & N. J. A. Sloane, <a href="/A005500/a005500.pdf">Correspondence, 1980-1981</a> %Y A005509 Row n=2 of the array in A169809. %K A005509 nonn %O A005509 0,2 %A A005509 _N. J. A. Sloane_ %E A005509 Terms a(6) and beyond from _Andrew Howroyd_, Feb 22 2021