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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.
1
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 28 2017
STATUS
approved