A153929 Number of planar n X n X n binary triangular grids symmetric under 120 degree rotation with no more than 4 ones in any 3 X 3 X 3 subtriangle.

1, 2, 2, 3, 13, 21, 81, 653, 2032, 13521, 198411, 1134105, 14051578, 384943878, 4075092077, 94920910164, 4841696508264, 95471746290629, 4126780473485202, 391264740388006351, 14349686703845230194, 1153837260755381339313

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Crossrefs

Sequence in context: A293445 A126339 A268725 * A184843 A100362 A062439

Adjacent sequences: A153926 A153927 A153928 * A153930 A153931 A153932

Keyword

nonn

Author

R. H. Hardin, Jan 03 2009

Status

approved