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A184556 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock summing to less than 4. 2
50, 336, 2167, 14180, 92429, 603249, 3935721, 25680486, 167558680, 1093290051, 7133495992, 46544663377, 303694712145, 1981548052649, 12929209539882, 84360538526896, 550435849841567, 3591485193655532, 23433731463177813 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A184564.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 6*a(n-1) + 7*a(n-2) - 23*a(n-3) - 4*a(n-4) + 12*a(n-5).

Empirical g.f.: x*(50 + 36*x - 199*x^2 - 24*x^3 + 108*x^4) / ((1 + 2*x)*(1 - 8*x + 9*x^2 + 5*x^3 - 6*x^4)). - Colin Barker, Feb 27 2018

EXAMPLE

Some solutions for 3 X 2:

..2..1....1..2....0..0....1..2....0..2....1..0....2..0....2..0....2..0....2..2

..2..1....2..0....2..2....1..1....2..1....2..2....1..1....1..2....1..2....2..1

..1..0....2..0....0..0....2..2....0..2....0..2....2..1....0..1....2..2....1..0

CROSSREFS

Cf. A184564.

Sequence in context: A124809 A261803 A184564 * A334697 A280548 A293608

Adjacent sequences:  A184553 A184554 A184555 * A184557 A184558 A184559

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 17 2011

STATUS

approved

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Last modified May 31 02:51 EDT 2020. Contains 334747 sequences. (Running on oeis4.)