A154040 Number of planar triangular n X n X n nonnegative integer grids symmetric under 120 degree rotation with every similarly oriented 4 X 4 X 4 subtriangle summing to 4.

4, 11, 13, 16, 13, 6, 10, 4, 6, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4

Offset

4,1

Comments

Value 4 starts at n=13 and continues through at least n=55.

Links

Table of n, a(n) for n=4..55.

Example

Maximal zeros solution for n=13
..............0
.............1.1
............0.1.0
...........0.0.0.1
..........1.0.1.0.0
.........0.0.1.1.0.0
........1.1.0.0.0.1.1
.......0.1.0.0.1.0.1.0
......0.0.0.1.1.0.0.0.1
.....1.0.1.0.0.1.0.1.0.0
....0.0.1.1.0.0.0.1.1.0.0
...1.1.0.0.0.1.1.0.0.0.1.1
..0.1.0.0.1.0.1.0.0.1.0.1.0

Crossrefs

Sequence in context: A268232 A285633 A266281 * A066985 A228003 A347561

Adjacent sequences: A154037 A154038 A154039 * A154041 A154042 A154043

Keyword

nonn

Author

R. H. Hardin Jan 04 2009

Status

approved