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!)
A252223 Number of (n+2) X (3+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4. 1
812, 3066, 9566, 24932, 73826, 231254, 718514, 2208224, 6786900, 20903022, 64397300, 198324482, 610719174, 1880738882, 5791972896, 17837010452, 54930710846, 169164213764, 520957422434, 1604338505654, 4940713885010 (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) = 3*a(n-1) - a(n-2) + 3*a(n-3) + 3*a(n-4) - a(n-5) - a(n-6) for n>8.

Empirical g.f.: 2*x*(406 + 315*x + 590*x^2 - 1568*x^3 - 1519*x^4 - 1188*x^5 - 519*x^6 + 147*x^7) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 3*x^2 - x^3)). - Colin Barker, Dec 02 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 3 of A252228.

Sequence in context: A183216 A093633 A045228 * A158667 A035854 A099116

Adjacent sequences:  A252220 A252221 A252222 * A252224 A252225 A252226

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 15 2014

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 October 17 17:21 EDT 2021. Contains 348065 sequences. (Running on oeis4.)