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A263870
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Number of (n+1)X(5+1) 0..1 arrays with each row and column divisible by 3, read as a binary number with top and left being the most significant bits, and rows and columns lexicographically nondecreasing.
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1
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4, 4, 14, 16, 61, 93, 494, 975, 4917, 10340, 41366, 85816, 280438, 562456, 1574783, 3040270, 7560914, 14059280, 31856173, 57181978, 120205886, 208862596, 412782291, 696193791, 1306513751, 2144538358, 3851037496, 6166629823
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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) = a(n-1) +18*a(n-2) -18*a(n-3) -153*a(n-4) +153*a(n-5) +816*a(n-6) -816*a(n-7) -3060*a(n-8) +3060*a(n-9) +8568*a(n-10) -8568*a(n-11) -18564*a(n-12) +18564*a(n-13) +31824*a(n-14) -31824*a(n-15) -43758*a(n-16) +43758*a(n-17) +48620*a(n-18) -48620*a(n-19) -43758*a(n-20) +43758*a(n-21) +31824*a(n-22) -31824*a(n-23) -18564*a(n-24) +18564*a(n-25) +8568*a(n-26) -8568*a(n-27) -3060*a(n-28) +3060*a(n-29) +816*a(n-30) -816*a(n-31) -153*a(n-32) +153*a(n-33) +18*a(n-34) -18*a(n-35) -a(n-36) +a(n-37)
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EXAMPLE
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Some solutions for n=4
..0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..0..0
..0..0..1..1..1..1....0..0..0..0..1..1....0..0..1..1..1..1....0..0..0..0..1..1
..0..0..1..1..1..1....0..0..0..0..1..1....0..0..1..1..1..1....0..0..0..0..1..1
..0..0..1..1..1..1....0..0..1..1..0..0....1..1..1..1..1..1....0..0..1..1..1..1
..0..0..1..1..1..1....0..0..1..1..0..0....1..1..1..1..1..1....0..0..1..1..1..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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