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A181258
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Number of (n+2)X6 binary matrices with every 3X3 block having exactly four 1's
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2
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2484, 3942, 6360, 10818, 22512, 48846, 112500, 289830, 764832, 2072106, 5854728, 16700214, 48109644, 140771982, 413533560, 1219726098, 3620006112, 10762255326, 32052060900, 95704407030, 285982189392, 855223829946, 2560357197048
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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)=4*a(n-1)-3*a(n-2)+36*a(n-3)-144*a(n-4)+108*a(n-5)-503*a(n-6)+2012*a(n-7)-1509*a(n-8)+3480*a(n-9)-13920*a(n-10)+10440*a(n-11)-12564*a(n-12)+50256*a(n-13)-37692*a(n-14)+22464*a(n-15)-89856*a(n-16)+67392*a(n-17)-15552*a(n-18)+62208*a(n-19)-46656*a(n-20)
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EXAMPLE
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Some solutions for 4X6
..0..1..1..0..0..1....1..0..0..1..0..1....0..0..1..0..0..1....0..1..0..1..1..0
..0..0..0..0..1..0....1..0..0..1..0..0....1..1..1..1..0..0....1..1..0..0..1..1
..0..1..1..0..1..1....1..0..1..1..0..0....0..0..0..0..1..1....0..0..1..0..0..0
..0..1..1..0..0..1....1..0..0..1..0..1....0..0..1..0..0..1....0..0..1..1..0..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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