A201535 Number of nX4 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor

6, 69, 633, 7799, 91425, 983981, 9526987, 82847704, 652848538, 4712696751, 31480011434, 196280028176, 1150650039753, 6380377582098, 33631853768986, 169225758487160, 815686475352515, 3777731764480697, 16854911299206527

Offset

1,1

Comments

Column 4 of A201539

Links

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

Formula

Empirical: a(n) is a polynomial of degree 80 for n>43

Example

Some solutions for n=5
..0..0..0..1....0..0..0..1....0..0..2..2....0..0..1..2....0..0..2..2
..0..0..2..1....0..0..0..1....0..2..2..2....1..1..1..2....0..1..0..0
..0..1..2..2....0..1..2..2....1..1..1..2....1..2..0..0....0..1..1..1
..1..1..1..0....2..1..2..0....1..2..0..0....2..2..2..2....2..0..0..2
..2..2..0..0....2..1..2..0....1..2..0..0....2..2..2..2....2..0..2..2

Crossrefs

Sequence in context: A183438 A296016 A288719 * A198699 A346938 A258792

Adjacent sequences: A201532 A201533 A201534 * A201536 A201537 A201538

Keyword

nonn

Author

R. H. Hardin Dec 02 2011

Status

approved