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!)
A296593 Number of n X 2 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 1, 2 or 3 neighboring 1s. 1
2, 11, 39, 136, 494, 1785, 6432, 23201, 83695, 301885, 1088905, 3927736, 14167501, 51102728, 184329596, 664884245, 2398264069, 8650634510, 31203185035, 112551137627, 405976459392, 1464373342374, 5282053272285, 19052577620620 (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) + a(n-2) + 4*a(n-3) + a(n-4) + a(n-6) - a(n-7) - a(n-8).

Empirical g.f.: x*(2 + 5*x + 4*x^2 + x^4 - 2*x^6 - x^7) / (1 - 3*x - x^2 - 4*x^3 - x^4 - x^6 + x^7 + x^8). - Colin Barker, Feb 23 2019

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Column 2 of A296599.

Sequence in context: A000175 A276659 A187259 * A125064 A274326 A055329

Adjacent sequences:  A296590 A296591 A296592 * A296594 A296595 A296596

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 16 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 10 22:11 EDT 2021. Contains 343780 sequences. (Running on oeis4.)