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A264055
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Number of (n+1) X (3+1) arrays of permutations of 0..n*4+3 with each element having index change +-(.,.) 0,0 1,2 or 2,-2.
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1
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4, 64, 324, 2025, 15625, 102400, 692224, 4826809, 32867289, 224820036, 1544804416, 10578122500, 72482100625, 496981290961, 3405885014016, 23343276294144, 160005726539569, 1096673231227249, 7516662847716100, 51520374361000000
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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) -a(n-2) +55*a(n-3) -385*a(n-4) +55*a(n-5) -385*a(n-6) +2695*a(n-7) -385*a(n-8) +385*a(n-9) -2695*a(n-10) +385*a(n-11) -55*a(n-12) +385*a(n-13) -55*a(n-14) +a(n-15) -7*a(n-16) +a(n-17).
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EXAMPLE
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Some solutions for n=4
..0..1..2..3....6..1..2..9....0..7..8..9....0..1..2..9....0..7..2..9
.10..5..6.13....4..5..0..7....4..5..6..1....4..5..6..7....4..5..6..1
..8..9..4.17....8..3.16.17....2..3.10.17....8..3.10.17...14..3.16.17
.18..7.14.15...18.13.14.15...12.19.14.15...18.19.14.15...12.19..8.15
.16.11.12.19...10.11.12.19...16.11.18.13...16.11.12.13...10.11.18.13
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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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