A269077 Number of 3 X n binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once.

8, 32, 123, 521, 1887, 7477, 27042, 102070, 368391, 1351259, 4850557, 17489481, 62373468, 222422348, 788291635, 2789267661, 9831173339, 34583332541, 121320954422, 424799241314, 1484281289599, 5177412026719, 18028809567225

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 8*a(n-2) - 34*a(n-3) - 16*a(n-4) + 60*a(n-5) - 25*a(n-6).

Empirical g.f.: x*(8 - 69*x^2 + 45*x^3 + 35*x^4 - 25*x^5) / (1 - 2*x - 6*x^2 + 5*x^3)^2. - Colin Barker, Jan 18 2019

Example

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

Crossrefs

Row 3 of A269075.

Sequence in context: A318944 A196097 A234272 * A183915 A357789 A363333

Adjacent sequences: A269074 A269075 A269076 * A269078 A269079 A269080

Keyword

nonn

Author

R. H. Hardin, Feb 19 2016

Status

approved