A154068 Number of planar triangular n X n X n nonnegative integer grids symmetric both under 120 degree rotation and reflection with every similarly oriented 4 X 4 X 4 subtriangle summing to 8.

4, 15, 7, 13, 4, 8, 3, 4, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset

4,1

Comments

Value 2 starts at n=16 and continues through at least n=60.

Links

Table of n, a(n) for n=4..60.

Example

Maximal zeros solution for n=16
.................2
................0.0
...............1.2.1
..............1.0.0.1
.............0.2.0.2.0
............2.0.1.1.0.2
...........0.0.2.0.2.0.0
..........1.2.1.0.0.1.2.1
.........1.0.0.1.2.1.0.0.1
........0.2.0.2.0.0.2.0.2.0
.......2.0.1.1.0.2.0.1.1.0.2
......0.0.2.0.2.0.0.2.0.2.0.0
.....1.2.1.0.0.1.2.1.0.0.1.2.1
....1.0.0.1.2.1.0.0.1.2.1.0.0.1
...0.2.0.2.0.0.2.0.2.0.0.2.0.2.0
..2.0.1.1.0.2.0.1.1.0.2.0.1.1.0.2

Crossrefs

Sequence in context: A328839 A143899 A379974 * A309526 A126601 A284119

Adjacent sequences: A154065 A154066 A154067 * A154069 A154070 A154071

Keyword

nonn

Author

R. H. Hardin, Jan 04 2009

Status

approved