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A209808
Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having two distinct values, and new values 0..3 introduced in row major order.
1
34, 302, 2721, 25505, 244208, 2377378, 23398105, 231987361, 2311229272, 23098641162, 231319042937, 2319549963665, 23278778523264, 233749081336914, 2347950341283193, 23589750833899361, 237038455370387400
OFFSET
1,1
COMMENTS
Column 2 of A209814.
LINKS
FORMULA
Empirical: a(n) = 17*a(n-1) - 68*a(n-2) - 56*a(n-3) + 397*a(n-4) - 181*a(n-5) - 264*a(n-6) + 108*a(n-7).
Empirical g.f.: x*(34 - 276*x - 101*x^2 + 1688*x^3 - 935*x^4 - 1182*x^5 + 504*x^6) / ((1 - 6*x - 3*x^2 + 2*x^3)*(1 - 11*x + 5*x^2 + 51*x^3 - 54*x^4)). - Colin Barker, Jul 13 2018
EXAMPLE
Some solutions for n=4:
..0..0..0....0..0..1....0..0..0....0..1..1....0..0..0....0..1..1....0..1..0
..1..1..1....1..0..0....0..1..0....0..0..1....0..1..1....0..0..0....0..1..0
..0..0..0....1..0..1....0..1..0....1..1..0....1..0..1....0..1..1....0..1..0
..1..0..1....0..0..0....1..1..0....0..0..0....1..0..0....1..1..2....1..0..0
..0..0..0....0..1..1....2..1..0....0..1..0....1..0..1....1..2..1....0..1..0
CROSSREFS
Cf. A209814.
Sequence in context: A156531 A220565 A230803 * A160146 A101092 A233061
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 13 2012
STATUS
approved