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A184002
Number of (n+1) X 9 0..2 arrays with all 2 X 2 subblock sums the same.
1
35535, 40041, 47031, 61125, 85431, 134853, 227319, 418461, 799815, 1612581, 3338151, 7206765, 16031991, 37247253, 89664279, 225444381, 586169895, 1579364421, 4360148871, 12326941005, 35353745751, 102812027253, 301213506039
OFFSET
1,1
COMMENTS
Column 8 of A184003.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) - 60*a(n-3) + 85*a(n-4) + 150*a(n-5) - 360*a(n-6) + 396*a(n-8) - 216*a(n-9).
Empirical g.f.: 3*x*(11845 - 57723*x - 64405*x^2 + 637013*x^3 - 299778*x^4 - 2096536*x^5 + 1958172*x^6 + 2114964*x^7 - 2396952*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)). - Colin Barker, Apr 09 2018
EXAMPLE
Some solutions for 3 X 9:
..1..2..0..1..1..0..0..2..0....0..0..2..1..1..2..2..1..0
..0..0..1..1..0..2..1..0..1....2..2..0..1..1..0..0..1..2
..1..2..0..1..1..0..0..2..0....0..0..2..1..1..2..2..1..0
CROSSREFS
Cf. A184003.
Sequence in context: A250978 A282129 A203337 * A205741 A206673 A205517
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2011
STATUS
approved