A153911 Number of planar n X n X n binary triangular grids symmetric under 120 degree rotation with no more than 2 ones in any 3 X 3 X 3 subtriangle.

1, 2, 412, 3309, 6170, 28173, 363650, 995263, 7017397, 125707566, 496907299, 5084773943, 131364083278, 749724226722, 10945594000512, 414717014027555, 3429998068477278, 72977331677447737, 3992874305065142952

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Crossrefs

Sequence in context: A352837 A352848 A349764 * A259562 A177321 A365520

Adjacent sequences: A153908 A153909 A153910 * A153912 A153913 A153914

Keyword

nonn

Author

R. H. Hardin, Jan 03 2009

Status

approved