A184131 Number of nX3 0..2 arrays with rows and columns in nondecreasing order

10, 112, 1169, 10020, 70243, 414848, 2126064, 9681099, 39886396, 150795172, 528970102, 1737120632, 5379657012, 15806662276, 44290055378, 118862126126, 306675218582, 763173754851, 1837012424988, 4287769072145, 9726214524190

Offset

1,1

Comments

Column 3 of A184137

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=27*a(n-1)-351*a(n-2)+2925*a(n-3)-17550*a(n-4)+80730*a(n-5)-296010*a(n-6)+888030*a(n-7)-2220075*a(n-8)+4686825*a(n-9)-8436285*a(n-10)+13037895*a(n-11)-17383860*a(n-12)+20058300*a(n-13)-20058300*a(n-14)+17383860*a(n-15)-13037895*a(n-16)+8436285*a(n-17)-4686825*a(n-18)+2220075*a(n-19)-888030*a(n-20)+296010*a(n-21)-80730*a(n-22)+17550*a(n-23)-2925*a(n-24)+351*a(n-25)-27*a(n-26)+a(n-27) (=polynomial of degree 26)

Example

Some solutions for 5X3
..0..1..2....0..0..1....0..0..1....0..0..2....0..0..2....0..1..1....0..1..1
..1..0..0....0..0..2....0..2..2....0..1..2....0..1..0....0..1..2....0..1..2
..1..1..2....1..2..1....1..1..0....1..1..1....1..1..0....0..2..2....2..0..0
..1..1..2....1..2..1....1..2..0....1..2..1....1..1..2....0..2..2....2..0..2
..1..1..2....1..2..1....2..2..0....1..2..2....2..2..2....2..0..1....2..2..1

Crossrefs

Sequence in context: A344398 A046164 A322724 * A239651 A014484 A110040

Adjacent sequences: A184128 A184129 A184130 * A184132 A184133 A184134

Keyword

nonn

Author

R. H. Hardin Jan 09 2011

Status

approved