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%I #12 Feb 24 2021 02:48:18
%S 0,5,9,17,30,42,52,69,90,102,112,129,150,170,196,237,274,286,296,313,
%T 334,354,380,421,458,478,504,545,590,642,724,829,898,910,920,937,958,
%U 978,1004,1045,1082,1102,1128,1169,1214
%N Toothpick sequence starting from an asymmetric cross, with four edges of length 1, 2, 3 and 4, formed by five toothpicks of length 2.
%C On the infinite square grid we start at stage 0 with no toothpicks. At stage 1 we place three consecutive toothpicks and two orthogonal toothpicks, as an asymetric cross with four edges of length 1, 2, 3, and 4, then a(1)=5. At stage 2 we place 4 toothpicks. And so on...
%C The sequence gives the number of toothpicks in the structure after n stages. A160427 (the first differences) gives the number added at the n-th stage. See A139250 for more information about toothpick sequences.
%H Nathaniel Johnston, <a href="/A160426/b160426.txt">Table of n, a(n) for n = 0..455</a>
%H David Applegate, Omar E. Pol and N. J. A. Sloane, <a href="/A000695/a000695_1.pdf">The Toothpick Sequence and Other Sequences from Cellular Automata</a>, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.]
%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>
%H Nathaniel Johnston, <a href="/A160426/a160426.c.txt">C program for computing terms</a>
%Y Cf. A139250, A139251, A160740, A160800, A160802, A160808.
%K nonn
%O 0,2
%A _Omar E. Pol_, May 25 2009, May 29 2009
%E Terms after a(13) from _Nathaniel Johnston_, Mar 31 2011
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