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A254847
Number of (n+2) X (1+2) 0..1 arrays with no 3 x 3 subblock diagonal sum one and no antidiagonal sum two.
1
192, 576, 1632, 4624, 13328, 38416, 110544, 318096, 913680, 2624400, 7549200, 21715600, 62425360, 179452816, 515960336, 1483482256, 4265261840, 12263347600, 35258287120, 101370918544, 291456195856, 837979129744, 2409294812688
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 8*a(n-3) + 12*a(n-4) + 20*a(n-5) + 32*a(n-6) - 64*a(n-8) - 64*a(n-9)
Empirical g.f.: 16*x*(12 + 24*x + 66*x^2 + 91*x^3 + 112*x^4 + 80*x^5 - 132*x^6 - 352*x^7 - 256*x^8) / ((1 + 2*x^2 - 4*x^3)*(1 + 2*x^2 + 4*x^3)*(1 - x - 4*x^2 - 4*x^3)). - Colin Barker, Dec 18 2018
EXAMPLE
Some solutions for n=4:
..0..0..0....1..1..0....0..1..0....1..1..1....0..1..0....1..0..0....1..0..1
..1..1..1....1..0..1....0..0..1....0..0..1....0..0..1....1..1..1....0..1..0
..0..1..1....1..1..1....0..1..0....0..1..1....0..0..0....0..0..1....1..0..1
..1..1..1....1..1..1....1..0..1....1..0..1....0..0..0....0..0..1....0..1..0
..1..0..1....1..1..0....0..1..0....0..1..0....0..1..0....0..0..0....1..0..0
..0..0..1....1..1..1....1..1..0....1..1..0....0..1..1....0..0..0....0..0..0
CROSSREFS
Column 1 of A254854.
Sequence in context: A229361 A232940 A254854 * A251083 A336944 A194647
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 08 2015
STATUS
approved