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!)
A282990 Number of nX2 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors. 4
4, 11, 33, 98, 291, 865, 2570, 7637, 22693, 67432, 200373, 595405, 1769236, 5257255, 15621845, 46420050, 137936399, 409875693, 1217938738, 3619084505, 10754048825, 31955475472, 94955158681, 282157659273, 838426745764, 2491370993875 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A282996.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +3*a(n-2) -a(n-4).

Empirical: G.f.: -x*(-4-3*x+x^2+x^3)/(1-2*x-3*x^2+x^4) . - R. J. Mathar, Mar 02 2017

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A282996.

Sequence in context: A143787 A289973 A236583 * A099159 A116394 A259442

Adjacent sequences:  A282987 A282988 A282989 * A282991 A282992 A282993

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 26 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 October 20 03:04 EDT 2021. Contains 348099 sequences. (Running on oeis4.)