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 A295560 #9 Dec 20 2017 14:19:46 %S A295560 0,1,4,10,16,22,34,52,64,70,82,100,118,136,166,208,232,238,250,268, %T A295560 286,304,334,376,406,424,454,496,538,580,646,736,784,790,802,820,838, %U A295560 856,886,928,958,976,1006,1048,1090,1132,1198,1288,1342,1360,1390,1432,1474 %N A295560 Same as A161644 except that triangles must always grow outwards. %D A295560 R. Reed, The Lemming Simulation Problem, Mathematics in School, 3 (#6, Nov. 1974), front cover and pp. 5-6. [Describes the dual structure where new triangles are joined at vertices rather than edges.] %H A295560 Lars Blomberg, <a href="/A295560/b295560.txt">Table of n, a(n) for n = 0..10000</a> %H A295560 R. Reed, <a href="/A005448/a005448_1.pdf">The Lemming Simulation Problem</a>, Mathematics in School, 3 (#6, Nov. 1974), front cover and pp. 5-6. [Scanned photocopy of pages 5, 6 only, with annotations by R. K. Guy and N. J. A. Sloane] %H A295560 N. J. A. Sloane, <a href="/A161644/a161644_1.png">Illustration of first 7 generations of A161644 and A295560 (edge-to-edge version)</a> %H A295560 N. J. A. Sloane, <a href="/A161644/a161644_2.png">Illustration of first 11 generations of A161644 and A295560 (vertex-to-vertex version)</a> [Include the 6 cells marked x to get A161644(11), exclude them to get A295560(11).] %H A295560 N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a> %Y A295560 Cf. A161644, A161645. %Y A295560 Partial sums of A295559. %K A295560 nonn %O A295560 0,3 %A A295560 _N. J. A. Sloane_, Nov 27 2017 %E A295560 Terms a(18) and beyond from _Lars Blomberg_, Dec 20 2017