Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #3 Mar 31 2012 12:35:23
%S 1,7,19,64,199,919,4123,24600,145752,1212971,10549470,114622513
%N Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 3,1 4,2 5,2 6,2 polyhexes in any orientation on a planar nXnXn triangular grid.
%e Maximal 11 X 11 X 11 example
%e .............0
%e ............0.0
%e ...........1.0.0
%e ..........0.1.0.0
%e .........0.0.1.1.1
%e ........0.0.0.0.0.1
%e .......0.0.1.0.0.0.1
%e ......0.0.1.0.0.0.0.0
%e .....1.1.1.0.0.0.1.1.1
%e ....1.0.0.0.0.0.1.0.0.0
%e ...1.0.0.0.1.1.1.0.0.0.0
%K nonn
%O 6,2
%A _R. H. Hardin_ Jan 22 2009