%I #9 Dec 20 2017 14:19:46
%S 0,1,4,10,16,22,34,52,64,70,82,100,118,136,166,208,232,238,250,268,
%T 286,304,334,376,406,424,454,496,538,580,646,736,784,790,802,820,838,
%U 856,886,928,958,976,1006,1048,1090,1132,1198,1288,1342,1360,1390,1432,1474
%N Same as A161644 except that triangles must always grow outwards.
%D 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 Lars Blomberg, <a href="/A295560/b295560.txt">Table of n, a(n) for n = 0..10000</a>
%H 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 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 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 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 Cf. A161644, A161645.
%Y Partial sums of A295559.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Nov 27 2017
%E Terms a(18) and beyond from _Lars Blomberg_, Dec 20 2017