A153988 Number of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with every one adjacent to exactly 2 other ones.

1, 1, 2, 2, 2, 4, 7, 7, 19, 30, 41, 111, 242, 341, 1198, 2798, 5288, 19451, 58386, 113037, 552176, 1717743, 4407296, 22107632, 91701868, 243757707, 1626825070, 6947686128, 24465641567, 168345671664, 954487204861, 3466462776895

Offset

0,3

Links

Table of n, a(n) for n=0..31.

Crossrefs

Sequence in context: A005865 A176051 A245257 * A253059 A098705 A029866

Adjacent sequences: A153985 A153986 A153987 * A153989 A153990 A153991

Keyword

nonn

Author

R. H. Hardin Jan 04 2009

Status

approved