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A263582
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Number of (n+1)X(1+1) arrays of permutations of 0..n*2+1 filled by rows with each element moved a city block distance of 1 or 2, and rows and columns in increasing lexicographic order.
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1
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1, 4, 18, 70, 292, 1212, 5028, 20832, 86360, 358008, 1484112, 6152272, 25503888, 105724928, 438276640, 1816850528, 7531649344, 31222019264, 129429085248, 536540828672, 2224199146368, 9220289638272, 38222180397312, 158447850514688
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OFFSET
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1,2
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COMMENTS
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Column 1 of A263586.
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = 4*a(n-1) +2*a(n-3) +4*a(n-4) -8*a(n-5).
Empirical: G.f.: -x*(-1-2*x^2+4*x^3) / ( 1-4*x-2*x^3-4*x^4+8*x^5 ). - R. J. Mathar, Nov 03 2015
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EXAMPLE
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Some solutions for n=4
..1..2....1..2....1..2....2..3....1..2....1..3....1..2....1..5....2..3....2..3
..3..0....5..0....3..0....5..0....3..0....4..0....4..0....4..0....4..0....4..0
..5..4....6..3....5..6....6..1....7..6....7..2....7..6....6..2....7..1....6..1
..7..8....8..4....8..4....7..4....8..4....8..5....8..3....8..3....8..5....7..8
..9..6....9..7....9..7....9..8....9..5....9..6....9..5....9..7....9..6....9..5
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CROSSREFS
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Cf. A263586.
Sequence in context: A171074 A005367 A050184 * A034352 A358463 A159715
Adjacent sequences: A263579 A263580 A263581 * A263583 A263584 A263585
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Oct 22 2015
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STATUS
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approved
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