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!)
A297369 Number of n X 3 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 0, 1 or 2 neighboring 1s. 1
8, 57, 393, 2719, 18805, 130063, 899565, 6221735, 43031893, 297624991, 2058487997, 14237288407, 98470518885, 681059680207, 4710468607821, 32579398179207, 225331548533621, 1558478965304063, 10779035164411613, 74551919956746807 (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) = 7*a(n-1) - 4*a(n-3).

Empirical g.f.: x*(8 + x - 6*x^2) / (1 - 7*x + 4*x^3). - Colin Barker, Feb 27 2019

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

CROSSREFS

Column 3 of A297374.

Sequence in context: A108666 A295711 A164031 * A023000 A331792 A097114

Adjacent sequences:  A297366 A297367 A297368 * A297370 A297371 A297372

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 29 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 March 28 11:49 EDT 2020. Contains 333083 sequences. (Running on oeis4.)