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!)
A281200 Number of n X 3 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1
1, 14, 56, 168, 448, 1120, 2688, 6272, 14336, 32256, 71680, 157696, 344064, 745472, 1605632, 3440640, 7340032, 15597568, 33030144, 69730304, 146800640, 308281344, 645922816, 1350565888, 2818572288, 5872025600, 12213813248, 25367150592 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) - 4*a(n-2) for n>3.
Conjectures from Colin Barker, Feb 16 2019: (Start)
G.f.: x*(1 + 10*x + 4*x^2) / (1 - 2*x)^2.
a(n) = 7*2^(n-1) * (n-1) for n>1.
(End)
EXAMPLE
Some solutions for n=4:
..0..1..0. .0..1..1. .0..0..1. .0..1..0. .0..0..1. .0..0..0. .0..1..1
..1..1..0. .0..1..0. .1..0..1. .0..1..1. .1..1..0. .1..1..0. .1..0..1
..0..1..0. .0..1..0. .1..0..1. .1..0..1. .0..1..0. .0..1..0. .1..0..1
..0..1..0. .0..1..0. .1..1..0. .1..0..0. .0..1..0. .0..1..1. .0..1..0
CROSSREFS
Column 3 of A281205.
Sequence in context: A192846 A212347 A115129 * A212341 A067326 A202242
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 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 February 29 23:21 EST 2024. Contains 370428 sequences. (Running on oeis4.)