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A280437
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Number of n X 5 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
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1
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5, 38, 77, 138, 225, 360, 574, 920, 1487, 2422, 3971, 6542, 10814, 17914, 29713, 49314, 81861, 135876, 225470, 373996, 620083, 1027598, 1702087, 2817898, 4662910, 7712270, 12749909, 21068730, 34800297, 57457632, 94828606, 156445952
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-3) + 4*a(n-4) - a(n-6) for n>7.
Empirical g.f.: x*(5 + 18*x - 55*x^2 - 8*x^3 + 37*x^4 + 14*x^5 + 7*x^6) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 13 2019
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EXAMPLE
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Some solutions for n=4:
..0..1..1..0..0. .0..0..1..0..0. .0..1..0..1..1. .0..1..0..1..0
..1..0..0..1..0. .1..1..0..1..0. .1..0..1..0..0. .1..0..1..0..1
..0..1..1..0..1. .0..0..1..0..1. .1..0..0..1..1. .0..1..0..0..1
..1..0..0..1..0. .1..1..0..1..0. .0..1..1..0..0. .1..0..1..1..0
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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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