A283095 Number of nX3 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements.

0, 6, 72, 600, 4607, 31669, 208949, 1324269, 8152245, 49070731, 289979290, 1687730558, 9698213032, 55123714128, 310376329220, 1733254750248, 9609161226263, 52931141892017, 289892095063747, 1579473182908079

Offset

1,2

Comments

Column 3 of A283100.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) +18*a(n-2) -52*a(n-3) -381*a(n-4) -543*a(n-5) +1654*a(n-6) +8943*a(n-7) +19026*a(n-8) +20615*a(n-9) +3639*a(n-10) -22728*a(n-11) -33125*a(n-12) -16047*a(n-13) +8640*a(n-14) +16878*a(n-15) +9570*a(n-16) +336*a(n-17) -3439*a(n-18) -2340*a(n-19) -477*a(n-20) +210*a(n-21) +216*a(n-22) +51*a(n-23) -13*a(n-24) -6*a(n-25) -3*a(n-26) +a(n-27)

Example

Some solutions for n=4
..1..0..1. .1..1..1. .1..0..1. .1..1..0. .0..0..1. .0..1..0. .0..0..1
..0..0..1. .0..0..0. .0..1..0. .1..0..0. .1..1..1. .1..0..1. .0..0..0
..0..1..1. .1..1..0. .1..1..1. .1..0..1. .0..0..1. .0..0..1. .0..1..1
..0..0..0. .1..0..0. .0..0..1. .0..1..0. .0..0..0. .0..1..1. .1..1..0

Crossrefs

Cf. A283100.

Sequence in context: A129532 A151719 A118313 * A281774 A036292 A061690

Adjacent sequences: A283092 A283093 A283094 * A283096 A283097 A283098

Keyword

nonn

Author

R. H. Hardin, Feb 28 2017

Status

approved