login
Number of planar triangular n X n X n nonnegative integer grids symmetric under 120 degree rotation with every similarly oriented 4 X 4 X 4 subtriangle summing to 9.
0

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

%S 20,60,123,304,180,208,509,248,136,220,132,58,42,78

%N Number of planar triangular n X n X n nonnegative integer grids symmetric under 120 degree rotation with every similarly oriented 4 X 4 X 4 subtriangle summing to 9.

%K nonn

%O 4,1

%A _R. H. Hardin_ Jan 04 2009