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!)
A230905 Number of n X 3 0..3 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero. 1
0, 8, 38, 152, 634, 2676, 11324, 47954, 203122, 860468, 3645314, 15443536, 65428104, 277194538, 1174373490, 4975404002, 21079033716, 89304460158, 378351663280, 1602943325236, 6791108946594, 28771548268074, 121894966018398 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 10*a(n-1) - 37*a(n-2) + 65*a(n-3) - 51*a(n-4) + 2*a(n-5) + 20*a(n-6) - 10*a(n-7) + 4*a(n-8) for n>11.

Empirical g.f.: 2*x^2*(4 - 21*x + 34*x^2 - 51*x^4 + 32*x^5 + 16*x^6 - 10*x^7 + x^8 - x^9) / ((1 - 2*x)*(1 - 8*x + 21*x^2 - 23*x^3 + 5*x^4 + 8*x^5 - 4*x^6 + 2*x^7)). - Colin Barker, Sep 22 2018

EXAMPLE

Some solutions for n=4:

..0..2..1....0..1..0....0..1..0....0..3..2....0..2..1....0..1..3....0..1..3

..1..3..2....2..3..2....3..2..1....1..0..1....1..3..0....3..2..0....3..2..0

..2..0..1....1..0..3....1..0..3....2..3..2....0..1..2....0..1..2....1..3..1

..1..3..2....3..1..2....3..2..1....1..0..1....3..0..3....3..0..3....0..2..0

CROSSREFS

Column 3 of A230910.

Sequence in context: A038799 A156934 A036684 * A026640 A122682 A225429

Adjacent sequences:  A230902 A230903 A230904 * A230906 A230907 A230908

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 01 2013

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 June 27 12:48 EDT 2022. Contains 354896 sequences. (Running on oeis4.)