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A204366 Number of (n+2) X 6 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
891, 713, 622, 704, 1264, 2956, 6772, 17852, 48260, 129860, 354004, 966724, 2637700, 7205348, 19685060, 53774276, 146912644, 401372740, 1096558660, 2995851716, 8184819524, 22361319236, 61092256324, 166907149636, 455998766404 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 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*(891 - 1960*x - 1517*x^2 - 1162*x^3 + 4498*x^4 + 3442*x^5 - 1928*x^6 - 1092*x^7 - 200*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..1..1..1..2....0..0..0..0..0..0....0..0..1..1..1..2....0..0..0..0..1..0

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

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

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

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

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

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

CROSSREFS

Cf. A204370.

Sequence in context: A006916 A128871 A110726 * A266915 A124666 A125303

Adjacent sequences:  A204363 A204364 A204365 * A204367 A204368 A204369

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 14 2012

STATUS

approved

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Last modified December 16 12:31 EST 2018. Contains 318160 sequences. (Running on oeis4.)