A217240 Number of triangular n X n X n arrays of occupancy after each element moves to some neighbor and with no occupancy greater than 2.

0, 7, 95, 6437, 1175140, 660602643

Offset

1,2

Comments

Column 2 of A217245.

Links

Table of n, a(n) for n=1..6.

Example

Some solutions for n=4
.....2........1........1........1........1........2........0........1
....0.2......0.1......1.1......1.1......2.1......0.1......1.2......0.1
...0.1.1....2.1.2....0.2.1....2.1.2....1.0.1....1.0.1....0.0.1....2.0.1
..0.1.2.1..2.1.0.0..0.2.0.2..1.0.1.0..2.0.2.0..2.2.1.0..1.2.1.2..1.0.2.2

Crossrefs

Cf. A217245.

Sequence in context: A156961 A239999 A054932 * A222834 A327676 A338075

Adjacent sequences: A217237 A217238 A217239 * A217241 A217242 A217243

Keyword

nonn,hard,more

Author

R. H. Hardin, Sep 28 2012

Status

approved