A223757 Number of nX3 0..3 arrays with rows, antidiagonals and columns unimodal

50, 2500, 61733, 916107, 9478535, 74824917, 477860225, 2571238699, 12006271464, 49749360288, 186123469150, 637408917764, 2020521264556, 5982701793264, 16672986760595, 44013068603319, 110650947588800, 266164581427718

Offset

1,1

Comments

Column 3 of A223762

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = (89/169374965760)*n^18 + (673039/29640619008000)*n^17 + (5753323/10461394944000)*n^16 + (20639/2335132800)*n^15 + (5460977/52306974720)*n^14 + (350675333/373621248000)*n^13 + (34569853/5225472000)*n^12 + (744079211/20118067200)*n^11 + (1214093389/7315660800)*n^10 + (3120210973/5225472000)*n^9 + (1381865894063/804722688000)*n^8 + (2224350329/574801920)*n^7 + (252375235967/37362124800)*n^6 + (1486577243227/163459296000)*n^5 + (2159143550149/217945728000)*n^4 + (154699301/14414400)*n^3 - (959722661/467812800)*n^2 + (50040773/6126120)*n + 1

Example

Some solutions for n=3
..1..1..3....1..2..2....0..0..2....1..3..1....0..1..3....3..2..1....0..3..2
..2..2..2....1..3..3....0..3..2....2..1..1....3..3..2....0..3..3....1..3..2
..2..2..0....1..3..3....0..1..3....0..1..3....3..1..0....0..2..2....1..2..1

Crossrefs

Sequence in context: A267061 A223191 A223807 * A223845 A223871 A223796

Adjacent sequences: A223754 A223755 A223756 * A223758 A223759 A223760

Keyword

nonn

Author

R. H. Hardin Mar 27 2013

Status

approved