login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A283409 Number of n X 2 0..1 arrays with no 1 equal to more than three of its horizontal, vertical and antidiagonal neighbors. 1
4, 16, 61, 236, 912, 3525, 13624, 52656, 203513, 786568, 3040048, 11749641, 45411804, 175514464, 678355061, 2621810068, 10133171296, 39164225421, 151367869744, 585029621920, 2261111681777, 8739089177552, 33776164295072 (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) = 3*a(n-1) + 3*a(n-2) + a(n-3) + a(n-4) + a(n-5).

Empirical g.f.: x*(4 + 4*x + x^2 + x^3 + x^4) / (1 - 3*x - 3*x^2 - x^3 - x^4 - x^5). - Colin Barker, Feb 21 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A283415.

Sequence in context: A206570 A206790 A283858 * A192468 A276042 A084859

Adjacent sequences:  A283406 A283407 A283408 * A283410 A283411 A283412

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 07 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 28 03:28 EDT 2022. Contains 354110 sequences. (Running on oeis4.)