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A264111
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Number of (1+1)X(n+1) arrays of permutations of 0..n*2+1 with each element having index change +-(.,.) 0,0 0,2 or 1,1.
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1
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2, 9, 45, 144, 512, 1936, 7381, 27225, 101250, 378225, 1413721, 5271616, 19668992, 73410624, 274002345, 1022528529, 3816059522, 14241796921, 53151529861, 198363344400, 740301120000, 2762842352400, 10311073884541, 38481439562281
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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) -a(n-2) +15*a(n-4) -60*a(n-5) +15*a(n-6) -15*a(n-8) +60*a(n-9) -15*a(n-10) +a(n-12) -4*a(n-13) +a(n-14)
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EXAMPLE
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Some solutions for n=4
..2..3..8..1..4....6..7..2..3..4....0..7..2..3..4....0..1..2..3..4
..5..0..9..6..7....5..0..1..8..9....5..6..1..8..9....5..8..7..6..9
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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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