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A204641 Number of (n+2) X 9 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
144255, 8140, 9750, 8179, 9482, 16171, 16636, 40170, 134630, 418053, 1557876, 5894935, 22113794, 83799892, 317716438, 1203888543, 4564208774, 17304289587, 65603583264, 248721866374, 942976402982, 3575089125409, 13554191367904 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A204642.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..121

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*(144255 - 713135*x + 401815*x^2 + 560869*x^3 + 1761457*x^4 - 1601082*x^5 - 3013092*x^6 + 1151934*x^7 + 1230813*x^8 + 1476*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..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1

..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1

..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1

..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1

..0..0..1..0..0..2..2..3..0....0..0..1..0..1..0..0..1..1

CROSSREFS

Cf. A204642.

Sequence in context: A004042 A145742 A236995 * A133324 A209968 A233915

Adjacent sequences:  A204638 A204639 A204640 * A204642 A204643 A204644

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 17 2012

STATUS

approved

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Last modified October 23 00:39 EDT 2021. Contains 348211 sequences. (Running on oeis4.)