A283125 Number of nX3 0..1 arrays with no 1 equal to more than two of its horizontal and vertical neighbors.

8, 57, 378, 2521, 16818, 112276, 749447, 5002276, 33388996, 222863968, 1487564143, 9929138252, 66274651117, 442367629539, 2952699342837, 19708570048557, 131550045689409, 878065454645686, 5860879322317997, 39119983879518589

Offset

1,1

Comments

Column 3 of A283130.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +7*a(n-2) +25*a(n-3) +18*a(n-4) +12*a(n-5) -20*a(n-6) -15*a(n-7) +3*a(n-8) +2*a(n-9).

Empirical: G.f.: -x*(8 +17*x +37*x^2 +32*x^3 -2*x^4 -33*x^5 -12*x^6 +5*x^7 +2*x^8)/(-1 +5*x +7*x^2 +25*x^3 +18*x^4 +12*x^5 -20*x^6 -15*x^7 +3*x^8 +2*x^9) . - R. J. Mathar, Mar 02 2017

Example

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

Crossrefs

Cf. A283130.

Sequence in context: A244201 A079926 A346228 * A108666 A295711 A164031

Adjacent sequences: A283122 A283123 A283124 * A283126 A283127 A283128

Keyword

nonn

Author

R. H. Hardin, Mar 01 2017

Status

approved