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A204640 Number of (n+2) X 8 0..3 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..3 introduced in row major order. 1
65096, 2239, 2517, 4366, 3077, 5446, 16171, 31929, 113429, 427632, 1544127, 5842306, 22153505, 83769619, 317569525, 1204018650, 4564128929, 17303859822, 65603984559, 248721637813, 942975124661, 3575090340268, 13554190693195 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 of A204642.

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) -3*a(n-2) -4*a(n-3) -12*a(n-4) +12*a(n-5) +21*a(n-6) -9*a(n-7) -9*a(n-8) for n>10.

Empirical g.f.: x*(65096 - 323241*x + 186610*x^2 + 258882*x^3 + 778906*x^4 - 741057*x^5 - 1348044*x^6 + 540753*x^7 + 561771*x^8 + 504*x^9) / ((1 - x)*(1 - x - x^2)*(1 - 3*x - 3*x^2)*(1 - 3*x^3)). - Colin Barker, Jun 08 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

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

CROSSREFS

Cf. A204642.

Sequence in context: A104939 A183975 A234908 * A015344 A184148 A083608

Adjacent sequences:  A204637 A204638 A204639 * A204641 A204642 A204643

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 17 2012

STATUS

approved

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Last modified December 6 06:14 EST 2021. Contains 349563 sequences. (Running on oeis4.)