A183467 Number of n X 2 binary arrays with every element equal to either the sum mod 2 of its vertical neighbors or the sum mod 2 of its horizontal neighbors.

2, 6, 12, 28, 68, 156, 368, 872, 2048, 4832, 11408, 26896, 63456, 149728, 353216, 833344, 1966144, 4638656, 10944000, 25820288, 60917760, 143723520, 339087616, 800010496, 1887468032, 4453111296, 10506243072, 24787422208, 58481067008

Offset

1,1

Comments

Column 2 of A183474.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 2*a(n-1) + 4*a(n-3) - 4*a(n-4) - 4*a(n-6).

Empirical g.f.: 2*x*(1 + x - 2*x^3 - 2*x^4 - 2*x^5) / ((1 - 2*x^3)*(1 - 2*x - 2*x^3)). - Colin Barker, Mar 29 2018

Example

Some solutions for 4 X 2:
..0..0....1..1....0..0....0..0....1..1....1..1....1..1....1..1....1..1....0..0
..0..0....1..0....1..1....0..0....0..0....0..0....1..1....1..1....0..0....1..1
..0..0....0..1....1..1....1..1....1..0....0..0....0..0....1..1....0..0....1..1
..0..0....1..1....0..0....1..1....1..0....1..1....0..0....0..0....0..0....1..1

Crossrefs

Cf. A183474.

Sequence in context: A191394 A237500 A330455 * A057582 A094779 A093387

Adjacent sequences: A183464 A183465 A183466 * A183468 A183469 A183470

Keyword

nonn

Author

R. H. Hardin, Jan 05 2011

Status

approved