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A183908
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Number of nondecreasing arrangements of n+2 numbers in 0..5 with each number being the sum mod 6 of two others.
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1
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2, 8, 37, 124, 309, 637, 1163, 1953, 3085, 4650, 6753, 9514, 13069, 17571, 23191, 30119, 38565, 48760, 60957, 75432, 92485, 112441, 135651, 162493, 193373, 228726, 269017, 314742, 366429, 424639, 489967, 563043, 644533, 735140, 835605, 946708
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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) = (1/120)*n^5 + (5/24)*n^4 + (49/24)*n^3 - (29/24)*n^2 - (461/20)*n + 43 for n>2.
G.f.: x*(2 - 4*x + 19*x^2 - 18*x^3 - 10*x^4 + 11*x^5 + 5*x^6 - 4*x^7) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>7.
(End)
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EXAMPLE
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All solutions for n=2:
..0....0....0....2....0....1....1....0
..2....0....0....2....2....2....3....3
..2....3....0....4....4....3....4....3
..4....3....0....4....4....5....5....3
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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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