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
Keywords
Examples
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
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
Comments