%I #20 Jul 07 2023 14:50:25
%S 0,2,2,2,4,2,4,4,4,6,4,6,8,2,4,4,6,10,6,14,8,10,14,8,12,14,4,8,8,10,
%T 16,12,22,16,16,18,12,14,16,16,16,10,12,20,14,22,22,18,18,24,18,28,18,
%U 20,28,22,28,20,18,18,22,32,32,26,24,22,28,28,32,34,20,20,28
%N Number of E-toothpicks (or tridents) added at n-th stage to the structure of the equilateral triangle of A220478.
%C Essentially the first differences of A220478.
%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) = 1 + A161331(n+1)/6 = 2*A211976(n).
%Y Cf. A139250, A139251, A160121, A161330, A161329, A161331, A211974, A211976.
%K nonn
%O 0,2
%A _Omar E. Pol_, Feb 19 2013