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A204364 Number of (n+2) X 4 0..2 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..2 introduced in row major order. 1
212, 466, 673, 713, 1715, 4355, 11671, 31891, 86275, 235547, 643475, 1756499, 4798531, 13109875, 35813875, 97844819, 267317171, 730318259, 1995265651, 5451167539, 14892855091, 40688034995, 111161779763, 303699607091 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A204370.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) -6*a(n-4) +4*a(n-6) for n>9.

Empirical g.f.: x*(212 - 170*x - 725*x^2 - 1306*x^3 + 848*x^4 + 2006*x^5 + 1796*x^6 - 708*x^7 - 1800*x^8) / ((1 - x)*(1 - 2*x - 2*x^2)*(1 - 2*x^3)). - Colin Barker, Jun 07 2018

EXAMPLE

Some solutions for n=5:

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

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

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

..0..0..0..0....0..0..0..0....0..0..0..0....2..2..2..2....0..0..0..0

..1..1..1..1....1..1..1..1....1..1..1..1....2..2..2..2....1..1..1..1

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

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

CROSSREFS

Cf. A204370.

Sequence in context: A251126 A078211 A158794 * A235180 A353139 A114880

Adjacent sequences:  A204361 A204362 A204363 * A204365 A204366 A204367

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 14 2012

STATUS

approved

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Last modified May 24 11:04 EDT 2022. Contains 354033 sequences. (Running on oeis4.)