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A255075
Number of (n+2) X (1+2) 0..1 arrays with no 3 x 3 subblock diagonal sum one and no antidiagonal sum one.
1
208, 676, 2444, 8836, 31960, 115600, 418200, 1512900, 5473500, 19802500, 71645000, 259210000, 937825000, 3393062500, 12276187500, 44415562500, 160696875000, 581406250000, 2103546875000, 7610701562500, 27535773437500, 99625351562500
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) - 25*a(n-3) + 25*a(n-4) for n>5.
Empirical g.f.: 4*x*(52 - 91*x - 234*x^2 + 454*x^3 - 130*x^4) / ((1 - 5*x + 5*x^2)*(1 - 5*x^2)). - Colin Barker, Dec 18 2018
EXAMPLE
Some solutions for n=4:
..1..1..1....1..1..1....1..1..0....1..1..1....0..0..0....1..0..0....0..1..1
..1..0..1....1..1..1....1..1..0....1..1..1....0..1..1....0..1..1....1..1..1
..1..1..1....1..1..0....1..1..1....1..1..0....1..1..1....1..1..1....0..1..1
..1..1..0....1..1..0....1..1..0....1..1..1....1..1..1....1..1..1....0..1..1
..1..1..0....1..0..0....1..1..1....1..0..1....0..1..0....1..1..0....1..1..1
..1..0..0....0..1..1....1..1..1....1..0..1....0..1..0....0..0..0....1..1..1
CROSSREFS
Column 1 of A255082.
Sequence in context: A131686 A235273 A255082 * A304281 A234549 A234543
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2015
STATUS
approved