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A188213
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Number of nondecreasing arrangements of 6 numbers in -(n+4)..(n+4) with sum zero.
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1
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338, 676, 1242, 2137, 3486, 5444, 8196, 11963, 17002, 23612, 32134, 42955, 56512, 73294, 93844, 118765, 148718, 184430, 226694, 276373, 334402, 401792, 479632, 569093, 671430, 787986, 920192, 1069575, 1237756, 1426456, 1637498, 1872809
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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) = 3*a(n-1) - 2*a(n-2) - a(n-3) + 2*a(n-5) - a(n-6) - a(n-7) + 2*a(n-8) - a(n-10) - 2*a(n-11) + 3*a(n-12) - a(n-13).
Empirical g.f.: x*(338 - 338*x - 110*x^2 + 101*x^3 + 235*x^4 - 174*x^5 - 41*x^6 + 279*x^7 - 83*x^8 - 217*x^9 - 146*x^10 + 395*x^11 - 151*x^12) / ((1 - x)^6*(1 + x)*(1 + x + x^2)*(1 + x + x^2 + x^3 + x^4)). - Colin Barker, Apr 27 2018
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EXAMPLE
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Some solutions for n=3:
.-3...-6...-6...-4...-6...-4...-5...-4...-5...-5...-4...-6...-4...-4...-6...-3
.-3...-2...-2...-3...-6...-2...-2...-3...-5...-4...-4...-5...-1...-3...-4...-3
.-3...-2...-1...-2...-5...-1...-2...-1...-2....0....0...-3...-1....0....0...-2
.-3....0....0...-2....5....0...-2...-1....3....2....0....4....0....2....0...-1
..5....4....3....4....6....3....4....4....4....2....4....4....2....2....5....3
..7....6....6....7....6....4....7....5....5....5....4....6....4....3....5....6
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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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