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A264107
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Number of (n+1) X (4+1) arrays of permutations of 0..n*5+4 with each element having index change +-(.,.) 0,0 0,2 or 1,1.
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1
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144, 2745, 54756, 1086300, 21511044, 426058380, 8439361956, 167165327340, 3311169794244, 65586863070540, 1299129134512356, 25732843496983980, 509710092283466244, 10096217247223673100, 199983489178768081956
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 19*a(n-1) + 304*a(n-3) + 256*a(n-4).
Empirical g.f.: 9*x*(16 + x + 289*x^2 + 240*x^3) / ((1 + 16*x^2)*(1 - 19*x - 16*x^2)). - Colin Barker, Jan 04 2019
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EXAMPLE
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Some solutions for n=3:
..0..7..2..3..4....0..3..8..1..4....0..3..8..1..4....0..3..4..1..2
.11..8..1..6..9...11..6..9..2..7....5.12.13..2..9....7..8.13..6..9
.10..5.14.19.12...10..5.14.19.12...10.11..6..7.14...12..5.10.11.14
.17.18.15.16.13...15.18.17.16.13...15.16.19.18.17...17.18.15.16.19
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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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