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A228256
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Number of third differences of arrays of length n+3 of numbers in 0..4.
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1
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33, 565, 6419, 53315, 315601, 1688101, 8717049, 44633821, 227363409, 1153594261, 5835080169, 29443836301, 148292923329, 745759583941, 3745977788889, 18798608421181, 94267920012849, 472439111692021, 2366593604971209
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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) = 9*a(n-1) - 20*a(n-2) for n>8.
G.f.: x*(33 + 268*x + 1994*x^2 + 6844*x^3 - 35854*x^4 - 86008*x^5 - 163840*x^6 - 57600*x^7) / ((1 - 4*x)*(1 - 5*x)).
a(n) = 5^(3+n) - 4^(3+n) for n>6.
(End)
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EXAMPLE
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Some solutions for n=4:
.12..-10....2...-7....8...-5....2..-13...-7..-15...-6...-3....5....3....7....2
.-7....8....3....6...-2....1....0...13....4....9....0....4...-2...-3..-12....3
.-1...-6....1....1...-1...-3...-7..-12....1....0....9...-1...-6....2...12...-1
..4....8...-7...-1...-4...-2...10...12...-6...-2..-13...-3...10...-5...-6....5
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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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