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A252712
Number of (n+2) X (1+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
39, 45, 54, 84, 111, 165, 257, 376, 560, 930, 1365, 2091, 3503, 5206, 8006, 13536, 20163, 31137, 52829, 78868, 122012, 207582, 310257, 480663, 819275, 1225618, 1900658, 3244188, 4856415, 7536909, 12878201, 19287760, 29950664, 51217434
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) + a(n-2) + 6*a(n-3) - 7*a(n-4) - 7*a(n-5) - 5*a(n-6) + 12*a(n-7) + 12*a(n-8) - 12*a(n-9) for n>11.
Empirical g.f.: x*(39 + 6*x - 30*x^2 - 249*x^3 - 24*x^4 + 234*x^5 + 365*x^6 + 11*x^7 - 436*x^8 + 84*x^9 + 12*x^10) / ((1 - x)^2*(1 + x)*(1 - 3*x^3)*(1 - 4*x^3)). - Colin Barker, Dec 05 2018
EXAMPLE
Some solutions for n=4:
..0..1..0....0..1..1....0..1..0....0..0..1....0..1..0....0..1..1....0..1..0
..0..0..2....1..0..1....2..2..0....2..1..1....2..2..0....1..0..1....1..2..1
..0..3..3....2..2..1....1..0..0....1..2..1....3..0..0....2..2..1....3..3..2
..0..2..0....3..1..1....0..1..0....0..0..1....0..3..0....3..1..1....0..0..3
..0..0..2....1..3..1....3..3..0....3..1..1....2..2..0....1..3..1....1..1..0
..0..1..1....2..2..1....1..0..0....1..3..1....1..1..0....0..0..1....2..2..1
CROSSREFS
Column 1 of A252719.
Sequence in context: A061756 A236673 A119028 * A252711 A046512 A143746
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2014
STATUS
approved