A153920 - OEIS

A153920

Number of planar n X n X n binary triangular grids symmetric under 120 degree rotation with no more than 3 ones in any 3 X 3 X 3 subtriangle.

%I #5 Apr 28 2021 00:16:21

%S 1,2,2,3,10,14,49,308,775,3862,41331,169669,1449423,25795923,

%T 176879439,2569800487,77632066170,900486220900,21773916434861,

%U 1104958273021411,21496112349545252,875306630139701071,74586189583189934357

%N Number of planar n X n X n binary triangular grids symmetric under 120 degree rotation with no more than 3 ones in any 3 X 3 X 3 subtriangle.

%K nonn

%O 0,2

%A _R. H. Hardin_, Jan 03 2009