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!)
A196012 Number of n X 3 0..4 arrays with each element equal to the number its horizontal and vertical neighbors within one of itself. 1
1, 1, 2, 7, 13, 16, 32, 65, 125, 211, 390, 732, 1368, 2478, 4555, 8417, 15564, 28583, 52598, 96921, 178684, 328956, 605723, 1115678, 2055336, 3785356, 6971537, 12840292, 23650713, 43560381, 80229677, 147768685, 272167135, 501285666 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Column 3 of A196017.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = a(n-1) +a(n-2) +3*a(n-4) -a(n-5) -2*a(n-6).

Empirical g.f.: x*(1 - x)*(1 + x + x^2 + 5*x^3 + 6*x^4) / (1 - x - x^2 - 3*x^4 + x^5 + 2*x^6). - Colin Barker, May 08 2018

EXAMPLE

All solutions for n=4:

..2..2..0....2..2..2....0..2..2....2..3..2....2..2..2....2..3..2....2..2..2

..3..3..2....2..0..2....2..3..3....3..4..3....2..0..2....3..3..3....2..0..2

..2..0..2....3..3..3....2..0..2....3..4..3....2..3..3....2..0..2....3..3..2

..2..2..2....2..3..2....2..2..2....2..3..2....0..2..2....2..2..2....2..2..0

CROSSREFS

Cf. A196017.

Sequence in context: A063222 A030592 A154313 * A065104 A138645 A191060

Adjacent sequences:  A196009 A196010 A196011 * A196013 A196014 A196015

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 26 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 11 20:03 EDT 2020. Contains 335652 sequences. (Running on oeis4.)