A153931 Number of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with no more than 4 ones in any 3 X 3 X 3 subtriangle.

1, 2, 2, 3, 5, 9, 17, 59, 104, 345, 1199, 3851, 12806, 82134, 263587, 1652702, 10527130, 63679653, 393522264, 4714694321, 28217205768, 327320006475, 3884899169563, 43662102002059, 501940164730369, 11189482352958319, 124569478026604902

Offset

0,2

Links

Table of n, a(n) for n=0..26.

Crossrefs

Sequence in context: A350432 A226956 A141602 * A214049 A273034 A208437

Adjacent sequences: A153928 A153929 A153930 * A153932 A153933 A153934

Keyword

nonn

Author

R. H. Hardin, Jan 03 2009

Status

approved