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A154043
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 5.
0
0, 20, 12, 0, 28, 6, 0, 18, 6, 0, 9, 0, 0, 9, 0, 0, 7, 0, 0, 9, 0, 0, 9, 0, 0, 9, 0, 0, 7, 0, 0, 9, 0, 0, 9, 0, 0, 9, 0, 0, 7, 0, 0, 9, 0, 0, 9, 0, 0, 9, 0, 0, 7, 0, 0, 9, 0, 0
OFFSET
3,2
COMMENTS
Pattern 0 9 0 0 9 0 0 7 0 0 9 0 starts at n=12 and continues through at least n=60.
EXAMPLE
Maximal zeros solution for n=13
..............3
.............0.0
............0.2.0
...........1.1.1.1
..........2.0.1.0.2
.........0.1.1.1.1.0
........1.1.0.2.0.1.1
.......0.1.2.0.0.2.1.0
......2.1.0.0.3.0.0.1.2
.....1.0.1.2.0.0.2.1.0.1
....0.1.1.1.0.2.0.1.1.1.0
...0.2.1.0.1.1.1.1.0.1.2.0
..3.0.0.1.2.0.1.0.2.1.0.0.3
CROSSREFS
Sequence in context: A071160 A071153 A209644 * A073868 A215028 A292558
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 04 2009
STATUS
approved