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!)
A269070 Number of n X 3 binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once. 1
7, 27, 123, 537, 2343, 10167, 43959, 189465, 814359, 3491691, 14937987, 63778065, 271799175, 1156345287, 4911870063, 20834207313, 88251723687, 373358554971, 1577691954507, 6659543294313, 28081651307943, 118299768626103 (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) = 10*a(n-1) - 31*a(n-2) + 24*a(n-3) + 21*a(n-4) - 18*a(n-5) - 9*a(n-6).

Empirical g.f.: x*(7 - 43*x + 70*x^2 - 24*x^3 - 9*x^4 - 9*x^5) / (1 - 5*x + 3*x^2 + 3*x^3)^2. - Colin Barker, Jan 18 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A269075.

Sequence in context: A118101 A201380 A327623 * A147996 A267365 A034536

Adjacent sequences:  A269067 A269068 A269069 * A269071 A269072 A269073

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 19 2016

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 7 03:48 EDT 2021. Contains 343636 sequences. (Running on oeis4.)