A155221 - OEIS

A155221

Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 2,2 polyhexes in any orientation on a planar nXnXn triangular grid.

%I #3 Mar 31 2012 12:35:22

%S 1,7,25,70,500,7410,81126,1254921,35099024,1318005942,58686994598,

%T 3824088664649,368413623404582,47231934784100638,8189977602765893624

%N Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 2,2 polyhexes in any orientation on a planar nXnXn triangular grid.

%e Maximal 9 X 9 X 9 example

%e ...........1

%e ..........1.1

%e .........0.0.1

%e ........1.0.0.0

%e .......1.1.0.0.1

%e ......1.0.0.1.1.1

%e .....0.0.1.0.0.0.0

%e ....1.0.0.1.1.0.1.0

%e ...1.1.1.0.1.0.1.1.1

%K nonn

%O 2,2

%A _R. H. Hardin_ Jan 22 2009