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%I #31 Mar 11 2014 01:34:19
%S 0,1,3,7,11,15,19,26,34,38,42,50,62,70,78,91,107,111,115,123,135,151,
%T 167,187,211,223,231,247,275,291,307,332,364,368,372,380,392,408,424,
%U 446,478,504,524,548,588,620,660,693,741,761,769,785,813,853,897,947
%N Number of toothpicks and D-toothpicks after n-th stage in the D-toothpick "narrow" triangle of the second kind.
%C If n = 2^k, k >= 1, then the structure looks like an isosceles triangle. For the D-toothpick "wide" triangle of the second kind see A194440.
%C The structure is essentially one of the wedges of several D-toothpick structures. For more information see A194270. The first differences (A194443) give the number of toothpicks or D-toothpicks added at n-th stage. - _Omar E. Pol_, Mar 28 2013
%H Omar E. Pol, <a href="http://www.polprimos.com/imagenespub/poltp064.jpg">Illustration of the structure after 32 stages</a>
%H Omar E. Pol, <a href="http://www.polprimos.com/imagenespub/poltp066.jpg">Illustration of the structure after 64 stages</a>
%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 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a>
%Y Cf. A047999, A139250, A160120, A160406, A161830, A194270, A194277, A194440, A194443, A194444, A194694, A194695, A194697, A220496, A220522.
%K nonn
%O 0,3
%A _Omar E. Pol_, Aug 29 2011