A215176 Number of nXnXn triangular 0..2 arrays with every horizontal row nondecreasing, first elements of rows nonincreasing, last elements of rows nondecreasing, and every row having the same average value

3, 4, 5, 9, 17, 48, 141, 559, 2231, 11148, 55733, 334389, 2006325, 14044264, 98309837, 786478683, 6291829451, 56626465044, 509638185381, 5096381853793, 50963818537913, 560602003917024, 6166622043087245, 73999464517046919

Offset

1,1

Comments

Column 2 of A215182

Links

R. H. Hardin, Table of n, a(n) for n = 1..89

Example

Some solutions for n=4
.....1........1........1........2........0........1........1........1
....1.1......1.1......1.1......2.2......0.0......1.1......0.2......1.1
...1.1.1....1.1.1....0.1.2....2.2.2....0.0.0....1.1.1....0.1.2....0.1.2
..0.0.2.2..0.1.1.2..0.0.2.2..2.2.2.2..0.0.0.0..1.1.1.1..0.0.2.2..0.1.1.2

Crossrefs

Sequence in context: A000692 A195971 A080552 * A063781 A257041 A346603

Adjacent sequences: A215173 A215174 A215175 * A215177 A215178 A215179

Keyword

nonn

Author

R. H. Hardin Aug 05 2012

Status

approved