A238649 - OEIS

A238649

Number of (n+2) X (3+2) 0..1 arrays with no element equal to all horizontal neighbors or equal to all vertical neighbors, and new values 0..1 introduced in row major order.

3, 18, 51, 189, 630, 2187, 7473, 25692, 88119, 302511, 1038144, 3563151, 12228903, 41971050, 144048471, 494389041, 1696791534, 5823557223, 19987023645, 68597444364, 235433215419, 808030095435, 2773239244320, 9518031521451

(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) = 2*a(n-1) + 5*a(n-2) - a(n-4).

Empirical g.f.: 3*x*(1 + 4*x - x^3) / (1 - 2*x - 5*x^2 + x^4). - Colin Barker, Oct 24 2018

EXAMPLE

Some solutions for n=5:

..0..1..1..0..1....0..1..0..1..0....0..1..0..1..0....0..1..0..0..1

..1..0..0..1..0....1..0..1..0..1....1..0..1..0..1....1..0..1..1..0

..1..0..1..0..1....0..1..0..0..1....0..1..0..1..0....0..1..0..1..0

..0..1..1..0..1....0..1..0..1..0....1..0..1..0..1....0..1..1..0..1

..1..0..0..1..0....1..0..1..0..1....0..1..0..1..0....1..0..1..1..0

..0..1..0..0..1....1..0..0..1..0....1..0..0..1..0....1..0..0..1..0

..1..0..1..1..0....0..1..1..0..1....0..1..1..0..1....0..1..1..0..1

CROSSREFS

Column 3 of A238654.

Sequence in context: A364599 A064043 A267639 * A375764 A268484 A085789

Adjacent sequences: A238646 A238647 A238648 * A238650 A238651 A238652

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 02 2014

STATUS

approved