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%I #22 Feb 04 2015 23:24:53
%S 0,1,1,1,2,1,2,3,4,1,2,3,5,5,4,7,8,1,2,3,5,5,5,9,13,9,4,7,12,14,10,16,
%T 16,1,2,3,5,5,5,9,13,9,5,9,15,19,17,21,29,17,4,7,12,14,14,22,34,30,14,
%U 16,28,35,25,35,32,1,2,3,5,5,5,9,13,9,5,9,15,19,17,21
%N a(n) = ceiling(A170905/2).
%C The hexagon-based CA of A151723 has as symmetry group the dihedral group of order 12. Consider a one-twelfth slice; a(n) is the number of cells that are turned from OFF to ON at generation n.
%F A170905(n) = 2a(n) except A170905(1)=1.
%e Illustration of generations 1 through 9:
%e .1
%e ..2
%e ...3
%e ..4.4
%e .....5
%e ..7.6.6
%e ...7...7
%e ..8.8.8.8
%e .........9
%e ...
%e From _Omar E. Pol_, Feb 12 2013: (Start)
%e When written as a triangle from 1, the right border gives A011782 and row lengths give A011782.
%e 1,
%e 1,
%e 1,2,
%e 1,2,3,4,
%e 1,2,3,5,5,4,7,8,
%e 1,2,3,5,5,5,9,13,9,4,7,12,14,10,16,16,
%e 1,2,3,5,5,5,9,13,9,5,9,15,19,17,21,29,17,4,7,12,14,14,22,34,30,14,16,28,35,25,35,32;
%e 1,2,3,5,5,5,9,13,9,5,9,15,19,17,21,... (End)
%Y Cf. A151723, A151724, A170905.
%K nonn,tabf
%O 0,5
%A _N. J. A. Sloane_, May 08 2010
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