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Search: id:A163704
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| A163704 |
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Number of nX2 binary arrays with all 1s connected, a path of 1s from left column to lower right corner, and no 1 having more than two 1s adjacent |
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+0
1
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| 1, 5, 11, 21, 38, 66, 112, 187, 309, 507, 828, 1348, 2190, 3553, 5759, 9329, 15106, 24454, 39580, 64055, 103657, 167735, 271416, 439176, 710618, 1149821, 1860467, 3010317, 4870814, 7881162, 12752008, 20633203, 33385245, 54018483, 87403764
(list; graph; listen)
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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..100
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FORMULA
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Empirical: a(n)=3*a(n-1)-2*a(n-2)-a(n-3)+a(n-4) for n>=6
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EXAMPLE
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All solutions for n=3
...0.0...0.0...0.0...0.0...1.0...0.1...1.1...0.0...1.0...1.1...1.1
...0.0...0.1...1.0...1.1...1.0...0.1...1.0...1.1...1.1...0.1...0.1
...1.1...1.1...1.1...1.1...1.1...1.1...1.1...0.1...0.1...0.1...1.1
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CROSSREFS
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Cf. A023548. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 06 2009]
Sequence in context: A164096 A163787 A166863 this_sequence A131898 A069097 A024921
Adjacent sequences: A163701 A163702 A163703 this_sequence A163705 A163706 A163707
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net) Aug 03 2009
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