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A277097
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a(n) = 5 - (prime(n) mod 10).
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0
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3, 2, 0, -2, 4, 2, -2, -4, 2, -4, 4, -2, 4, 2, -2, 2, -4, 4, -2, 4, 2, -4, 2, -4, -2, 4, 2, -2, -4, 2, -2, 4, -2, -4, -4, 4, -2, 2, -2, 2, -4, 4, 4, 2, -2, -4, 4, 2, -2, -4, 2, -4, 4, 4, -2, 2, -4, 4, -2, 4, 2, 2, -2, 4, 2, -2, 4, -2, -2, -4, 2
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OFFSET
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1,1
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COMMENTS
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Except for a(1)=3 and a(3)=5 the entries are either {-4, -2, 2, 4} and occur in roughly equal ratios. - Robert G. Wilson v, Nov 04 2016
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LINKS
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FORMULA
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EXAMPLE
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For n = 10 and prime(10) = 29, so a(10) = 5 - 9 = -4.
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MATHEMATICA
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PROG
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(PARI) a(n) = my(p=prime(n)); (10*(p\10)+5) - p; \\ Michel Marcus, Sep 30 2016
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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STATUS
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approved
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