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A263966
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Number of (2+1)X(n+1) arrays of permutations of 0..n*3+2 with each element having index change (+-,+-) 0,0 1,1 or 1,2.
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1
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9, 141, 2089, 23841, 283641, 3408145, 40723017, 484847873, 5770449785, 68675639729, 817318275497, 9726917755361, 115759353325657, 1377648247909137, 16395387308054025, 195121651065350465, 2322144975436013241
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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) = 13*a(n-1) +6*a(n-2) -262*a(n-3) +488*a(n-4) -652*a(n-5) -7720*a(n-6) +52376*a(n-7) +108848*a(n-8) +259552*a(n-9) -852288*a(n-10) -6712576*a(n-11) +8309504*a(n-12) +21286400*a(n-13) -24625664*a(n-14) -121656320*a(n-15) -32204800*a(n-16) +612724736*a(n-17) -186105856*a(n-18) -728727552*a(n-19) +2890399744*a(n-20) -617873408*a(n-21) -6594756608*a(n-22) +4604821504*a(n-23) +3544186880*a(n-24) -9990832128*a(n-25) -8069840896*a(n-26) +6744440832*a(n-27) +4026531840*a(n-28) for n>30
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EXAMPLE
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Some solutions for n=4
..7..1..9..6..8....0..1..5..3..8....0..5..8..3..4....7..1..9..6..4
..2.12..0..4..3....2..6..4.14.13....1.13..7..2.12....2..0.11.12..3
.10.11..5.13.14...10.11.12..9..7...10.11..9..6.14...10..8..5.13.14
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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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