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!)
A198279 Number of 2n X 4 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors. 1
1, 4, 14, 52, 190, 700, 2574, 9476, 34878, 128396, 472654, 1739988, 6405438, 23580508, 86807566, 319567268, 1176432574, 4330837036, 15943242574, 58692346740, 216065933246, 795410139132, 2928167715854, 10779553536580 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 2 of A198285.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +a(n-2) -8*a(n-3).
Empirical g.f.: x*(1 - 3*x^2) / (1 - 4*x - x^2 + 8*x^3). - Colin Barker, May 14 2018
EXAMPLE
Some solutions for n=3:
..0..0..1..1....0..0..1..1....0..0..0..0....0..0..1..1....0..0..1..1
..0..0..1..1....0..0..1..1....0..1..1..0....0..0..1..1....0..0..1..1
..1..1..2..2....2..2..2..2....0..1..1..0....2..2..0..0....2..2..2..2
..1..1..2..2....2..0..0..2....0..0..0..0....2..2..0..0....2..1..1..2
..0..0..1..1....2..0..0..2....2..2..1..1....0..0..2..2....2..1..1..2
..0..0..1..1....2..2..2..2....2..2..1..1....0..0..2..2....2..2..2..2
CROSSREFS
Cf. A198285.
Sequence in context: A058692 A165813 A253199 * A211307 A369577 A099486
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 23 2011
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 March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)