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A228221
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Number of second differences of arrays of length 6 of numbers in 0..n.
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1
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63, 665, 3151, 9705, 23351, 47953, 88215, 149681, 238735, 362601, 529343, 747865, 1027911, 1380065, 1815751, 2347233, 2987615, 3750841, 4651695, 5705801, 6929623, 8340465, 9956471, 11796625, 13880751, 16229513, 18864415, 21807801, 25082855
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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) = 35*n^4 + 14*n^3 - 17*n^2 + 30*n + 1.
G.f.: x*(63 + 350*x + 456*x^2 - 30*x^3 + x^4) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.
(End)
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EXAMPLE
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Some solutions for n=4:
..4....5....6...-2...-5....5...-6....5....7...-2....0....3...-1....4...-2....3
..0...-2...-3...-3...-1....0....3...-3...-5....3...-4...-5....5....0....1...-2
.-4....5....0....1....2...-4....2....3....5...-1....4....0...-6...-3....1...-2
..1...-8....5....1...-1....2...-5...-4...-7...-2....2....3....7....0....4....4
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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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