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A206233
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Number of (n+1) X 4 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly two equal edges, and new values 0..3 introduced in row major order.
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1
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310, 1136, 4456, 27168, 133392, 607008, 3503136, 17206032, 78302496, 451903008, 2219576592, 10101020448, 58295486496, 286325378832, 1303031636256, 7520117756448, 36935973867792, 168091081075488, 970095190580256
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = a(n-1) + 129*a(n-3) - 129*a(n-4) for n>7.
Empirical g.f.: 2*x*(155 + 413*x + 1660*x^2 - 8639*x^3 - 165*x^4 + 22668*x^5 - 16860*x^6) / ((1 - x)*(1 - 129*x^3)). - Colin Barker, Jun 14 2018
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EXAMPLE
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Some solutions for n=4:
..0..1..2..0....0..0..1..0....0..0..1..0....0..0..1..1....0..0..1..0
..3..2..2..0....0..1..0..0....2..0..0..2....1..1..0..1....2..0..0..1
..2..2..1..2....1..0..0..1....3..1..0..0....2..1..1..0....3..1..0..0
..2..1..2..2....0..0..2..3....3..3..1..0....1..2..1..1....3..3..1..0
..3..2..2..3....1..1..3..3....1..3..3..1....1..1..0..0....0..3..3..1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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