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A281211
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Number of 7 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal 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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0, 1308, 2688, 3604, 5712, 9118, 14375, 22700, 36144, 58168, 94524, 154800, 254959, 421560, 698756, 1159898, 1926760, 3201376, 5318733, 8833940, 14666360, 24337820, 40366132, 66914912, 110866187, 183590176, 303864300, 502685950, 831204864
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OFFSET
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1,2
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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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>13.
Empirical g.f.: x^2*(1308 - 2544*x - 1916*x^2 + 4664*x^3 + 830*x^4 - 2793*x^5 - 12*x^6 + 920*x^7 + 274*x^8 + 40*x^9 - 18*x^10 - 10*x^11) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 18 2019
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EXAMPLE
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Some solutions for n=4:
..0..1..0..1. .0..0..1..0. .0..0..1..0. .0..1..0..1. .0..1..1..0
..0..0..0..1. .1..0..1..0. .1..0..1..0. .1..0..1..0. .0..0..1..0
..0..1..0..1. .1..1..1..0. .0..1..0..1. .1..0..1..0. .1..0..1..0
..0..1..0..0. .0..0..1..0. .0..1..0..1. .1..0..1..0. .0..1..0..1
..0..1..1..0. .1..0..1..0. .0..0..1..0. .0..1..1..0. .0..1..1..1
..0..0..1..0. .1..0..1..0. .1..0..1..0. .0..0..1..0. .0..1..0..1
..1..0..1..1. .0..1..0..1. .0..1..0..1. .1..0..1..0. .0..1..0..0
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CROSSREFS
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Row 7 of A281205.
Sequence in context: A126841 A106815 A325605 * A233975 A209853 A165936
Adjacent sequences: A281208 A281209 A281210 * A281212 A281213 A281214
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Jan 17 2017
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STATUS
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approved
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