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A254733
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a(n) is the least k > n such that n divides k^3.
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4
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2, 4, 6, 6, 10, 12, 14, 10, 12, 20, 22, 18, 26, 28, 30, 20, 34, 24, 38, 30, 42, 44, 46, 30, 30, 52, 30, 42, 58, 60, 62, 36, 66, 68, 70, 42, 74, 76, 78, 50, 82, 84, 86, 66, 60, 92, 94, 60, 56, 60, 102, 78, 106, 60, 110, 70, 114, 116, 118, 90, 122, 124, 84
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OFFSET
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1,1
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COMMENTS
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A073353(n) <= a(n) <= 2*n. Any prime that divides n must also divide a(n), and because n divides (2*n)^3.
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LINKS
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FORMULA
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EXAMPLE
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a(8) = 10 because 8 divides 10^3, but 8 does not divide 9^3.
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PROG
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(Ruby)
def a(n)
(n+1..2*n).find { |k| k**3 % n == 0 }
end
(PARI) a(n)=for(k=n+1, 2*n, if(k^3%n==0, return(k)))
vector(100, n, a(n)) \\ Derek Orr, Feb 07 2015
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CROSSREFS
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Cf. A019555 (similar without the restriction that a(n) > n).
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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