A154038 Number of planar triangular n X n X n nonnegative integer grids with mirror symmetry about one altitude with every similarly oriented 3 X 3 X 3 subtriangle summing to 4.

14, 25, 24, 27, 22, 18, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15, 16, 15, 15

Offset

3,1

Comments

Pattern 15 16 15 starts at n=9 and continues through at least n=60.

Links

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

Example

Maximal zeros solution for n=9
..........2
.........0.0
........0.2.0
.......2.0.0.2
......0.0.2.0.0
.....0.2.0.0.2.0
....2.0.0.2.0.0.2
...0.0.2.0.0.2.0.0
..0.2.0.0.2.0.0.2.0

Crossrefs

Sequence in context: A141838 A140499 A068365 * A366960 A061923 A031075

Adjacent sequences: A154035 A154036 A154037 * A154039 A154040 A154041

Keyword

nonn

Author

R. H. Hardin Jan 04 2009

Status

approved