cp's OEIS Frontend

A184408 Number of holes in the toothpick structure of A182840.

%I A184408 #24 Jul 20 2019 14:22:51
%S A184408 0,0,0,0,0,0,0,2,6,6,6,6,6,8,12,18,30,30,30,30,30,30,30,34,46,56,60,
%T A184408 60,60,66,80,98,126,126,126,126,126,126,126,130,142,150,150,150,150,
%U A184408 154,166,186,222,248,252,252,252,252,252,260,288,322,344,348,348,364,404,450,510,510,510,510,510,510,510,514,526
%N A184408 Number of holes in the toothpick structure of A182840.
%C A184408 Each connected group of unoccupied lines in the hexagonal structure enclosed by toothpicks counts as a hole.
%H A184408 Olaf Voß, <a href="/A184408/b184408.txt">Table of n, a(n) for n = 0..625</a>
%H A184408 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 A184408 Olaf Voß, <a href="/wiki/Toothpick_structures_on_hexagonal_net">Toothpick structures on hexagonal net</a>
%H A184408 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a>
%e A184408 Structure after step 8:
%e A184408       \_/
%e A184408     \_/ \_/
%e A184408   \_/ \_/ \_/
%e A184408 \_/  _/ \_  \_/
%e A184408 / \_/ \_/ \_/ \
%e A184408 \_/ \_/ \_/ \_/
%e A184408 / \ / \_/ \ / \
%e A184408 \_/ \_/ \_/ \_/
%e A184408 / \_/ \_/ \_/ \
%e A184408 \_/ \_/ \_/ \_/
%e A184408 / \_  \_/  _/ \
%e A184408   / \_/ \_/ \
%e A184408     / \_/ \
%e A184408       / \
%e A184408 There are 6 holes in this structure, so a(8)=6.
%Y A184408 For total number of missing toothpicks see A184409.
%K A184408 nonn
%O A184408 0,8
%A A184408 _Olaf Voß_, Jan 13 2011