A204146 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A204146

Number of (n+2) X 3 0..2 arrays with every 3 X 3 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..2 introduced in row major order.

689, 3902, 22262, 127022, 724154, 4128422, 23538722, 134209022, 765199994, 4362829142, 24874945682, 141826072622, 808630145834, 4610454909062, 26286795128642, 149875795721822, 854526159123674, 4872133976736182

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 1 of A204153.

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) -5*a(n-2) +20*a(n-3) -4*a(n-4) -16*a(n-5).

Empirical g.f.: x*(689 - 232*x + 2295*x^2 - 820*x^3 - 1952*x^4) / ((1 - x)*(1 + 4*x^2)*(1 - 5*x - 4*x^2)). - Colin Barker, Jun 06 2018

EXAMPLE

Some solutions for n=4:

..0..0..0....0..1..1....0..1..0....0..0..0....0..0..1....0..0..1....0..1..0

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

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

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

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

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

CROSSREFS

Cf. A204153.

Sequence in context: A025355 A025347 A204153 * A259512 A078877 A204145

Adjacent sequences: A204143 A204144 A204145 * A204147 A204148 A204149

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 11 2012

STATUS

approved