%I #16 Mar 24 2013 13:51:07
%S 0,1,2,2,2,4,6,4,2,4,8,8,6,10,14,8,2,4,8,12,16
%N Number of pentagons added at n-th stage to the structure of A222176.
%C Essentially the first differences of A222176.
%C Also number of P-toothpicks added at n-th stage to the P-toothpick structure of A222176.
%C First differs from A152968 at a(10).
%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>
%F a(n) = A222181(n+1)/5, n >= 1.
%e Apparently this is an irregular triangle:
%e 0;
%e 1;
%e 2, 2;
%e 2, 4, 6, 4;
%e 2, 4, 8, 8, 6, 10, 14, 8;
%e 2, 4, 8, 12, 16,...
%Y Cf. A139251, A152968, A222173, A222176, A222180, A222181.
%K nonn,tabf,more
%O 0,3
%A _Omar E. Pol_, Mar 21 2013
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