A228386 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

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