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A264373
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Number of (n+1)X(2+1) arrays of permutations of 0..n*3+2 with each element having directed index change 2,-2 -1,0 -1,2 1,0 or 0,-1.
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1
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2, 1, 13, 25, 128, 347, 1343, 4172, 14711, 48187, 164644, 549209, 1857120, 6231551, 21001218, 70602740, 237686843, 799548823, 2690789595, 9053237740, 30464275277, 102504319825, 344916282634, 1160576447091, 3905173385325, 13140236820844
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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) +13*a(n-2) -4*a(n-3) -57*a(n-4) +11*a(n-5) +138*a(n-6) -25*a(n-7) -213*a(n-8) +38*a(n-9) +220*a(n-10) -26*a(n-11) -151*a(n-12) -7*a(n-13) +62*a(n-14) +19*a(n-15) -21*a(n-16) -8*a(n-17) +7*a(n-18) +a(n-19) -a(n-20)
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EXAMPLE
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Some solutions for n=4
..1..2..3....1..4..3....3..2..5....3..4..5....3..4..5....1..4..3....1..4..3
..0..7..6....0..7..8....0..1..6....0..1..6....0..1..8....0..7..6....0..5..6
..9..4..5....2.10..5....7..4..9....2..8..9....2.10..9....2..8..5....2.10..9
.12.13.14....6.13.12...12.13.14...12..7.14....6..7.12...12.13.14...12..7..8
..8.10.11....9.14.11....8.10.11...13.10.11...13.14.11....9.10.11...13.14.11
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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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