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A186467
Number of (n+1) X 5 0..2 arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors.
1
367, 562, 1203, 3186, 4875, 9834, 14883, 31866, 51057, 105398, 174289, 347428, 588058, 1145866, 1976438, 3787644, 6625638, 12540516, 22170114, 41575892, 74087098, 137980420, 247343794, 458282956, 825184634, 1523024532, 2751516210
OFFSET
1,1
COMMENTS
Column 4 of A186472.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + 4*a(n-4) - 2*a(n-5) for n>13.
Empirical g.f.: x*(367 - 172*x - 288*x^2 + 1686*x^3 - 1920*x^4 + 196*x^5 - 604*x^6 + 1428*x^7 - 1350*x^8 + 1364*x^9 + 36*x^10 - 18*x^11 + 9*x^12) / ((1 - x)*(1 - x - 2*x^2 + 2*x^3 - 2*x^4)). - Colin Barker, Apr 18 2018
EXAMPLE
Some solutions for 3 X 5:
..0..0..0..1..1....1..2..0..2..0....1..2..0..0..0....2..0..0..0..0
..0..0..0..0..1....2..0..2..0..2....2..0..2..0..0....0..2..0..0..0
..2..0..0..0..0....0..2..0..2..1....0..2..0..2..0....0..0..2..0..0
CROSSREFS
Cf. A186472.
Sequence in context: A320711 A142236 A307009 * A054827 A059230 A212378
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 22 2011
STATUS
approved