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A185742 Number of (n+1) X 2 binary arrays with every 2 X 2 subblock trace equal to some horizontal or vertical neighbor 2 X 2 subblock trace. 2
0, 24, 40, 144, 344, 1000, 2688, 7528, 20648, 57040, 156920, 432648, 1192128, 3286216, 9056584, 24960464, 68789400, 189584296, 522495232, 1440006312, 3968670312, 10937688528, 30144344504, 83078054856, 228963805504 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 1 of A185750.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - a(n-2) - 2*a(n-3) + 8*a(n-4).
Empirical g.f.: 8*x^2*(3 - 4*x + 6*x^2) / (1 - 3*x + x^2 + 2*x^3 - 8*x^4). - Colin Barker, Feb 28 2018
EXAMPLE
Some solutions for 3 X 2:
..0..1....1..0....1..1....1..0....0..1....1..0....0..0....1..1....0..1....1..0
..0..1....1..0....0..0....1..0....0..0....1..1....0..1....1..0....1..1....0..0
..0..1....1..0....1..1....0..0....0..0....0..1....0..1....0..0....1..0....0..1
CROSSREFS
Cf. A185750.
Sequence in context: A357699 A328375 A141717 * A286876 A181702 A304890
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 01 2011
STATUS
approved

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Last modified April 17 17:01 EDT 2024. Contains 371765 sequences. (Running on oeis4.)