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A188501
Number of n X 2 binary arrays without the pattern 0 1 0 diagonally, vertically or horizontally.
10
4, 16, 49, 144, 441, 1369, 4225, 12996, 40000, 123201, 379456, 1168561, 3598609, 11082241, 34128964, 105103504, 323676081, 996791184, 3069714025, 9453478441, 29112890625, 89655929476, 276104007936, 850288696321, 2618545348864
OFFSET
1,1
COMMENTS
Column 2 of A188508.
LINKS
FORMULA
Empirical: a(n)=3*a(n-1)-a(n-2)+3*a(n-3)+3*a(n-4)-a(n-5)-a(n-6).
Empirical g.f.: x*(4 + 4*x + 5*x^2 + x^3 - 2*x^4 - x^5) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 3*x^2 - x^3)). - Colin Barker, Feb 18 2018
EXAMPLE
Some solutions for 3 X 2:
..1..1....0..1....1..1....1..1....0..1....1..0....0..1....1..1....1..1....0..1
..1..0....1..0....1..1....0..0....0..1....1..0....0..0....0..1....0..1....0..0
..1..0....1..0....1..0....1..0....1..1....0..1....1..1....1..1....1..0....1..0
CROSSREFS
Sequence in context: A227266 A114185 A188516 * A283692 A173712 A085697
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 02 2011
STATUS
approved