A228386 Number of n X 4 binary arrays with top left value 1 and no two ones adjacent horizontally or vertically.

3, 12, 72, 382, 2104, 11449, 62546, 341249, 1862631, 10165343, 55480071, 302792766, 1652555713, 9019158650, 49223917246, 268649627276, 1466210540982, 8002145144295, 43673350799304, 238356282199103, 1300878367732021

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +9*a(n-2) -5*a(n-3) -4*a(n-4) +a(n-5).

Empirical g.f.: x*(3 - 3*x^2 + x^3) / (1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5). - Colin Barker, Sep 11 2018

Example

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

Crossrefs

Column 4 of A228390.

Sequence in context: A335643 A277457 A367117 * A175836 A293138 A319948

Adjacent sequences: A228383 A228384 A228385 * A228387 A228388 A228389

Keyword

nonn

Author

R. H. Hardin, Aug 21 2013

Status

approved