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A200194
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Number of -n..n arrays x(0..4) of 5 elements with zero sum, adjacent elements differing by more than one, and elements alternately increasing and decreasing.
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1
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0, 24, 144, 506, 1298, 2794, 5300, 9220, 14974, 23094, 34120, 48712, 67524, 91346, 120950, 157254, 201146, 253672, 315838, 388820, 473738, 571896, 684534, 813084, 958900, 1123544, 1308488, 1515422, 1745934, 2001842, 2284852, 2596912, 2939842
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 2*a(n-1) -a(n-3) -2*a(n-5) +2*a(n-6) +a(n-8) -2*a(n-10) +a(n-11).
Empirical g.f.: 2*x^2*(12 + 48*x + 109*x^2 + 155*x^3 + 171*x^4 + 133*x^5 + 79*x^6 + 26*x^7 + 3*x^8) / ((1 - x)^5*(1 + x)^2*(1 + x^2)*(1 + x + x^2)). - Colin Barker, May 20 2018
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EXAMPLE
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Some solutions for n=5:
..0...-2...-3...-5...-2...-2...-4...-4....0....0....2....2...-5....1...-4....1
.-3....2....4....4....2....5....2....1...-3...-2...-2...-4....4...-2....3...-4
..4...-4....0....0....0...-2...-5...-1....5....2....4....3...-3....2...-1....3
.-3....4....2....3....3....4....5....3...-5...-5...-5...-5....4...-4....4...-2
..2....0...-3...-2...-3...-5....2....1....3....5....1....4....0....3...-2....2
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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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