login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A283125 Number of nX3 0..1 arrays with no 1 equal to more than two of its horizontal and vertical neighbors. 1
8, 57, 378, 2521, 16818, 112276, 749447, 5002276, 33388996, 222863968, 1487564143, 9929138252, 66274651117, 442367629539, 2952699342837, 19708570048557, 131550045689409, 878065454645686, 5860879322317997, 39119983879518589 (list; graph; refs; listen; history; text; internal format)
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: A282394 A244201 A079926 * A108666 A295711 A164031

Adjacent sequences:  A283122 A283123 A283124 * A283126 A283127 A283128

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 01 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 31 05:50 EDT 2020. Contains 334747 sequences. (Running on oeis4.)