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A240480
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Number of nX4 0..1 arrays with no element equal to more than two horizontal or vertical neighbors, with new values 0..1 introduced in row major order
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1
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8, 81, 578, 4104, 29084, 205754, 1455916, 10304849, 72937769, 516249590, 3653997013, 25862854244, 183056241833, 1295664762145, 9170663523390, 64909590438320, 459427491120642, 3251809452014192, 23016177558642426
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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) = 7*a(n-1) +2*a(n-2) -7*a(n-3) -25*a(n-4) -6*a(n-5) +150*a(n-6) +12*a(n-7) -456*a(n-8) -134*a(n-9) +408*a(n-10) +116*a(n-11) -171*a(n-12) +73*a(n-13) +388*a(n-14) +87*a(n-15) -127*a(n-16) -168*a(n-17) -62*a(n-18) -12*a(n-19) +16*a(n-20) +8*a(n-21) +2*a(n-22)
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EXAMPLE
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Some solutions for n=4
..0..0..1..0....0..1..0..0....0..1..1..1....0..1..1..0....0..0..1..0
..1..0..1..0....1..0..1..1....0..1..0..0....1..0..1..0....1..1..0..1
..1..0..1..1....1..1..0..1....1..0..0..1....0..1..0..1....1..1..0..1
..1..0..0..1....0..1..1..1....1..0..1..1....1..0..1..0....0..0..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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