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A252250 Number of (n+2) X (4+2) 0..3 arrays with every 3 X 3 subblock row and column sum not equal to 0 3 5 6 or 7 and every 3 X 3 diagonal and antidiagonal sum equal to 0 3 5 6 or 7. 1
352, 268, 249, 267, 297, 336, 384, 462, 564, 690, 894, 1161, 1491, 2025, 2724, 3588, 4986, 6816, 9078, 12738, 17529, 23451, 33033, 45576, 61080, 86166, 119004, 159594, 225270, 311241, 417507, 589449, 814524, 1092732, 1542882, 2132136, 2860494 (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) = a(n-1) + 3*a(n-3) - 3*a(n-4) - a(n-6) + a(n-7) for n>9.

Empirical g.f.: x*(352 - 84*x - 19*x^2 - 1038*x^3 + 282*x^4 + 96*x^5 + 346*x^6 - 96*x^7 - 34*x^8) / ((1 - x)*(1 - 3*x^3 + x^6)). - Colin Barker, Dec 02 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 4 of A252254.

Sequence in context: A220686 A167820 A145633 * A235888 A256025 A256771

Adjacent sequences:  A252247 A252248 A252249 * A252251 A252252 A252253

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 16 2014

STATUS

approved

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Last modified October 26 02:14 EDT 2021. Contains 348256 sequences. (Running on oeis4.)