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A252108 Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and column sum equal to 0 2 3 6 or 7 and every 3 X 3 diagonal and antidiagonal sum not equal to 0 2 3 6 or 7. 1
1929, 1424, 724, 584, 624, 788, 1180, 1668, 2472, 3888, 5640, 8592, 13920, 20496, 31776, 52416, 77856, 121920, 203136, 303168, 477312, 799488, 1196160, 1888512, 3171840, 4751616, 7512576, 12635136, 18940416, 29967360, 50436096, 75629568 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-3) - 8*a(n-6) for n>13.

Empirical g.f.: x*(1929 + 1424*x + 724*x^2 - 10990*x^3 - 7920*x^4 - 3556*x^5 + 13108*x^6 + 9316*x^7 + 3536*x^8 + 1480*x^9 + 624*x^10 + 64*x^11 + 32*x^12) / ((1 - 2*x^3)*(1 - 4*x^3)). - Colin Barker, Dec 01 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 2 of A252114.

Sequence in context: A099482 A253337 A200435 * A220717 A162386 A283925

Adjacent sequences:  A252105 A252106 A252107 * A252109 A252110 A252111

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 14 2014

STATUS

approved

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Last modified May 26 21:56 EDT 2022. Contains 354092 sequences. (Running on oeis4.)