A203537 Number of nX3 0..2 arrays with every element neighboring horizontally or vertically both a 0 and a 1

0, 4, 72, 144, 1840, 10404, 69920, 490000, 3317120, 22524516, 153723240, 1044840976, 7112904336, 48420242116, 329561076960, 2243249071504, 15269163209664, 103931377966276, 707427841294920, 4815226903450896

Offset

1,2

Comments

Column 3 of A203542

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -8*a(n-3) -38*a(n-4) +218*a(n-5) +400*a(n-6) -2936*a(n-7) +609*a(n-8) -2791*a(n-9) +4072*a(n-10) +248*a(n-11) -588*a(n-12) +4916*a(n-13) -1912*a(n-14) +8920*a(n-15) -7799*a(n-16) +3393*a(n-17) -5960*a(n-18) -464*a(n-19) -238*a(n-20) +18*a(n-21) -56*a(n-22) -9*a(n-24) -a(n-25)

Example

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

Crossrefs

Sequence in context: A227248 A113839 A077112 * A095385 A071683 A192826

Adjacent sequences: A203534 A203535 A203536 * A203538 A203539 A203540

Keyword

nonn

Author

R. H. Hardin Jan 02 2012

Status

approved