A185835 T(n,k)=Half the number of nXk binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

0, 1, 1, 1, 3, 1, 2, 10, 10, 2, 3, 23, 30, 23, 3, 5, 61, 118, 118, 61, 5, 8, 162, 393, 514, 393, 162, 8, 13, 421, 1430, 2398, 2398, 1430, 421, 13, 21, 1103, 5004, 11789, 15782, 11789, 5004, 1103, 21, 34, 2890, 17877, 54223, 98975, 98975, 54223, 17877, 2890, 34, 55

Offset: 1

Author

R. H. Hardin Feb 05 2011

Keywords

• nonn
• tabl

Comments

Table starts

..0....1......1.......2.........3..........5............8............13

..1....3.....10......23........61........162..........421..........1103

..1...10.....30.....118.......393.......1430.........5004.........17877

..2...23....118.....514......2398......11789........54223........257050

..3...61....393....2398.....15782......98975.......649826.......4143707

..5..162...1430...11789.....98975.....923808......7678409......68363184

..8..421...5004...54223....649826....7678409.....91052720....1073661088

.13.1103..17877..257050...4143707...68363184...1073661088...17200095426

.21.2890..63181.1213538..26679121..593948668..12644950311..278159538826

.34.7563.224324.5716561.171597547.5187350050.149729950026.4418356392225

Examples

			Some solutions for 5X4 with a(1,1)=0
..0..0..1..1....0..0..0..1....0..0..1..1....0..0..1..0....0..0..0..0
..1..0..1..1....0..1..0..1....0..1..1..0....0..1..1..0....0..1..1..1
..1..1..0..0....1..1..0..0....1..1..0..0....0..1..0..0....0..1..0..0
..0..0..0..1....1..0..1..0....0..0..1..1....1..0..1..1....0..1..0..0
..1..1..1..1....0..0..1..1....1..1..0..0....1..0..0..1....0..1..1..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..219

Crossrefs

Column 1 is A000045(n-1)