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A179953
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a(n) is the least exponent k such that q^k >= n, where q is the greatest prime factor of n (= A006530(n)); a(1) = 1 by convention.
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1
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1, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 3, 1, 2, 2, 4, 1, 3, 1, 2, 2, 2, 1, 3, 2, 2, 3, 2, 1, 3, 1, 5, 2, 2, 2, 4, 1, 2, 2, 3, 1, 2, 1, 2, 3, 2, 1, 4, 2, 3, 2, 2, 1, 4, 2, 3, 2, 2, 1, 3, 1, 2, 3, 6, 2, 2, 1, 2, 2, 3, 1, 4, 1, 2, 3, 2, 2, 2, 1, 3, 4, 2, 1, 3, 2, 2, 2, 2, 1, 3, 2, 2, 2, 2, 2, 5, 1, 3, 2, 3, 1, 2, 1, 2, 3, 2
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OFFSET
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1,4
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COMMENTS
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Previous name was: a(n) is the least integer such that the greatest prime factor of n is greater than or equal to its a(n)th root.
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LINKS
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MATHEMATICA
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Table[n = 1; m = Max[FactorInteger[x][[All, 1]]]; While[x^(1/n) > m, ++n]; n, {x, START, END}]
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PROG
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(PARI)
A006530(n) = if(1==n, n, vecmax(factor(n)[, 1]));
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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a(1) = 1 prepended and definition rewritten by Antti Karttunen, Oct 20 2017
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STATUS
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approved
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