A153899 Number of planar n X n X n binary triangular grids symmetric under 120-degree rotation with no more than 1 one in any 3 X 3 X 3 subtriangle.

1, 2, 1, 1, 3, 4, 6, 13, 17, 34, 101, 146, 325, 1195, 2277, 6460, 27376, 61961, 214755, 1116386, 3024411, 12485340, 79544755, 263062079, 1324332721, 10146383904, 40752385354, 249319033030, 2314746073775, 11234416498141, 83071107149999

Offset

0,2

Links

Table of n, a(n) for n=0..30.

Crossrefs

Sequence in context: A124424 A057044 A372760 * A068098 A135722 A258306

Adjacent sequences: A153896 A153897 A153898 * A153900 A153901 A153902

Keyword

nonn

Author

R. H. Hardin, Jan 03 2009

Status

approved