A154054 Number of planar triangular n X n X n nonnegative integer grids symmetric under 120 degree rotation with every similarly oriented 3 X 3 X 3 subtriangle summing to 6.

3, 30, 17, 20, 88, 16, 18, 110, 28, 14, 82, 12, 28, 76, 12, 12, 86, 12, 12, 76, 28, 12, 76, 12, 28, 76, 12, 12, 86, 12, 12, 76, 28, 12, 76, 12, 28, 76, 12, 12, 86, 12, 12, 76, 28, 12, 76, 12, 28, 76, 12, 12, 86, 12, 12, 76, 28, 12

Offset

3,1

Comments

Pattern 12 28 76 12 12 86 12 12 76 28 12 76 starts at n=14 and continues through at least n=60.

Links

Table of n, a(n) for n=3..60.

Example

Maximal zeros solution for n=14
...............2
..............2.2
.............0.0.0
............0.2.2.0
...........2.0.2.0.2
..........2.2.0.0.2.2
.........0.0.0.4.0.0.0
........0.2.2.0.0.2.2.0
.......2.0.2.0.2.0.2.0.2
......2.2.0.0.2.2.0.0.2.2
.....0.0.0.4.0.0.0.4.0.0.0
....0.2.2.0.0.2.2.0.0.2.2.0
...2.0.2.0.2.0.2.0.2.0.2.0.2
..2.2.0.0.2.2.0.0.2.2.0.0.2.2

Crossrefs

Sequence in context: A078242 A108739 A072973 * A118219 A186681 A295430

Adjacent sequences: A154051 A154052 A154053 * A154055 A154056 A154057

Keyword

nonn

Author

R. H. Hardin Jan 04 2009

Status

approved