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A185791
Number of (n+1) X 3 binary arrays with no 2 X 2 subblock sum equal to any horizontal or vertical neighbor 2 X 2 subblock sum.
1
40, 96, 224, 576, 1408, 3456, 8320, 20864, 50816, 125312, 304768, 756096, 1844864, 4548992, 11110016, 27429248, 67069568, 165194112, 404309632, 995805568, 2438669952, 6000273792, 14703462016, 36167944576, 88660698752, 217982249344
OFFSET
1,1
COMMENTS
Column 2 of A185798.
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) + 16*a(n-4) - 16*a(n-5).
Empirical g.f.: 8*x*(5 + 7*x + 6*x^2 + 20*x^3 - 32*x^4) / (1 - x - 2*x^2 - 16*x^4 + 16*x^5). - Colin Barker, Apr 16 2018
EXAMPLE
Some solutions for 5 X 3:
..0..1..0....1..1..1....1..0..0....0..0..1....0..0..0....0..0..1....0..1..1
..1..0..0....0..1..1....0..0..0....0..0..1....1..1..0....0..0..1....0..1..1
..0..0..0....0..0..1....0..0..1....0..1..1....1..0..1....1..1..1....0..0..0
..0..0..1....0..0..0....1..0..1....0..1..1....0..1..1....1..0..0....1..1..0
..0..1..1....1..0..0....0..1..1....0..0..0....0..0..0....0..0..0....1..0..1
CROSSREFS
Cf. A185798.
Sequence in context: A279689 A063310 A211493 * A092889 A235280 A235271
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 04 2011
STATUS
approved