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URL: https://oeis.org/A184665

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A184665
Number of (n+1) X 2 0..3 arrays with no 2 X 2 subblock summing to less than 6.
2
150, 1740, 19269, 216912, 2430631, 27278035, 305991368, 3432961182, 38513146024, 432071200891, 4847297854288, 54380688812185, 610083824961241, 6844384156411424, 76785501492801006, 861438105302681684
OFFSET
1,1
COMMENTS
Column 1 of A184673.
LINKS
FORMULA
Empirical: a(n) = 10*a(n-1) + 25*a(n-2) - 123*a(n-3) - 73*a(n-4) + 304*a(n-5) + 36*a(n-6) - 144*a(n-7).
Empirical g.f.: x*(150 + 240*x - 1881*x^2 - 828*x^3 + 4756*x^4 + 432*x^5 - 2304*x^6) / (1 - 10*x - 25*x^2 + 123*x^3 + 73*x^4 - 304*x^5 - 36*x^6 + 144*x^7). - Colin Barker, Feb 27 2018
EXAMPLE
Some solutions for 3 X 2:
..0..1....0..0....2..0....2..1....3..2....0..2....1..3....3..1....3..0....3..1
..2..3....3..3....3..3....2..1....1..3....3..3....3..1....3..1....2..3....3..3
..0..1....2..0....3..3....1..2....2..2....2..1....3..1....3..1....2..1....1..0
CROSSREFS
Cf. A184673.
Sequence in context: A073614 A191547 A184673 * A088361 A206041 A151607
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 19 2011
STATUS
approved