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A252726
Number of (7+2) X (n+2) 0..3 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.
1
257, 220, 224, 257, 288, 324, 373, 452, 512, 617, 768, 900, 1093, 1412, 1664, 2057, 2688, 3204, 3973, 5252, 6272, 7817, 10368, 12420, 15493, 20612, 24704, 30857, 41088, 49284, 61573, 82052, 98432, 123017, 163968, 196740, 245893, 327812, 393344
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = -a(n-1) + 3*a(n-3) + 3*a(n-4) - 2*a(n-6) - 2*a(n-7) for n>9.
Empirical g.f.: x*(257 + 477*x + 444*x^2 - 290*x^3 - 886*x^4 - 720*x^5 - 232*x^6 + 144*x^7 + 16*x^8) / ((1 - x)*(1 + x)*(1 + x + x^2)*(1 - 2*x^3)). - Colin Barker, Dec 06 2018
EXAMPLE
Some solutions for n=4:
..0..1..1..0..1..1....0..1..1..0..1..1....0..1..0..0..1..0....0..0..1..0..0..2
..0..2..0..0..3..0....1..0..1..1..0..1....1..1..2..1..1..2....0..3..3..0..3..3
..0..0..2..0..0..3....2..2..1..2..2..1....3..1..1..2..1..1....0..1..0..0..1..0
..0..1..1..0..1..1....0..1..1..0..1..1....0..1..0..0..1..0....0..0..1..0..0..1
..0..3..0..0..2..0....1..0..1..1..0..1....1..1..3..1..1..2....0..3..3..0..3..3
..0..0..3..0..0..2....2..2..1..2..2..1....3..1..1..3..1..1....0..2..0..0..1..0
..0..1..1..0..1..1....3..1..1..0..1..1....0..1..0..0..1..0....0..0..2..0..0..1
..0..3..0..0..3..0....1..3..1..1..0..1....1..1..3..1..1..3....0..3..3..0..3..3
..0..0..3..0..0..3....2..2..1..2..2..1....2..1..1..3..1..1....0..2..0..0..2..0
CROSSREFS
Row 7 of A252719.
Sequence in context: A273775 A182912 A276233 * A260679 A043676 A296901
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2014
STATUS
approved