A194135 Number of ways to arrange 7 indistinguishable points on an n X n X n triangular grid so that no three points are collinear at any angle.

0, 0, 0, 0, 9, 1875, 52323, 695616, 5840088, 35715529, 172520643, 708871152, 2517687856, 8023634766, 23292994812, 62357664744, 155765126265, 367482996726, 822866800569, 1762214894004, 3621792301059

Offset

1,5

Comments

Column 7 of A194136.

Links

Table of n, a(n) for n=1..21.

Example

Some solutions for 5 X 5 X 5:
......0..........0..........0..........0..........0..........0..........0
.....0.1........1.0........1.0........0.1........0.1........1.0........1.1
....1.0.1......1.0.1......0.1.1......1.1.0......1.1.0......0.1.1......0.0.1
...1.0.1.0....0.1.0.1....1.0.0.1....1.0.0.1....0.0.1.1....1.1.0.0....1.1.0.0
..0.1.0.1.0..0.1.0.1.0..0.1.1.0.0..0.0.1.1.0..1.0.1.0.0..0.0.1.0.1..0.0.1.1.0

Crossrefs

Sequence in context: A068182 A368368 A218415 * A114224 A201845 A218692

Adjacent sequences: A194132 A194133 A194134 * A194136 A194137 A194138

Keyword

nonn

Author

R. H. Hardin, Aug 17 2011

Status

approved