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A207124
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Number of 4Xn 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 0 1 1 vertically
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1
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9, 81, 289, 1024, 4096, 14161, 45796, 150544, 481636, 1493284, 4601025, 14055001, 42380100, 126900225, 378108025, 1119906225, 3301766521, 9702250000, 28419216400, 83012558161, 241951836996, 703860593296, 2044150748644
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OFFSET
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1,1
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COMMENTS
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Row 4 of A207123
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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) = 6*a(n-1) -12*a(n-2) +30*a(n-3) -105*a(n-4) +140*a(n-5) -191*a(n-6) +637*a(n-7) -525*a(n-8) +374*a(n-9) -2132*a(n-10) +851*a(n-11) -82*a(n-12) +4997*a(n-13) -364*a(n-14) -761*a(n-15) -7828*a(n-16) -1358*a(n-17) +1552*a(n-18) +7812*a(n-19) +2336*a(n-20) -1168*a(n-21) -4944*a(n-22) -1472*a(n-23) +512*a(n-24) +1632*a(n-25) +448*a(n-26) -128*a(n-27) -256*a(n-28)
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EXAMPLE
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Some solutions for n=4
..0..0..0..0....1..1..1..1....0..0..0..0....1..0..0..0....0..1..1..0
..0..1..1..0....1..1..1..1....0..1..1..1....1..0..0..0....1..0..1..1
..0..0..0..0....1..1..1..1....0..0..0..0....1..0..0..0....0..0..0..0
..0..0..0..0....1..1..1..0....0..1..1..1....0..0..0..0....1..0..1..1
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CROSSREFS
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Sequence in context: A207904 A207748 A208035 * A207854 A207962 A207501
Adjacent sequences: A207121 A207122 A207123 * A207125 A207126 A207127
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin Feb 15 2012
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STATUS
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approved
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