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A204379 Number of (n+2) X 8 0..1 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..1 introduced in row major order. 1
286, 128, 139, 153, 176, 217, 283, 388, 559, 837, 1284, 2009, 3183, 5080, 8151, 13121, 21160, 34169, 55219, 89276, 144383, 233549, 377820, 611257, 988967, 1600112, 2588967, 4188969, 6777824, 10966681, 17744395, 28710964, 46455247, 75166101 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 of A204381.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +a(n-2) +a(n-3) -a(n-4) -a(n-5) for n>8.

Empirical g.f.: x*(286 - 158*x - 275*x^2 - 400*x^3 + 42*x^4 + 163*x^5 + 4*x^6 + 4*x^7) / ((1 - x)*(1 - x - x^2)*(1 + x + x^2)). - Colin Barker, Jun 07 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

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

CROSSREFS

Cf. A204381.

Sequence in context: A231422 A146893 A090089 * A025384 A256000 A253329

Adjacent sequences:  A204376 A204377 A204378 * A204380 A204381 A204382

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 14 2012

STATUS

approved

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Last modified September 21 21:32 EDT 2021. Contains 347605 sequences. (Running on oeis4.)