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A179953 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. 1

%I

%S 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,

%T 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,

%U 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

%N 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.

%C 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.

%H Antti Karttunen, <a href="/A179953/b179953.txt">Table of n, a(n) for n = 1..16384</a>

%t Table[n = 1; m = Max[FactorInteger[x][[All, 1]]]; While[x^(1/n) > m, ++n]; n, {x, START, END}]

%o (PARI)

%o A006530(n) = if(1==n, n, vecmax(factor(n)[, 1]));

%o A179953(n) = { my(q = A006530(n), m = q, k=1); while(m < n, m *= q; k++); k; }; \\ _Antti Karttunen_, Oct 20 2017

%Y Cf. A006530.

%K easy,nonn

%O 1,4

%A _Dylan Hamilton_, Aug 03 2010

%E a(1) = 1 prepended and definition rewritten by _Antti Karttunen_, Oct 20 2017

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Last modified January 19 17:45 EST 2019. Contains 319309 sequences. (Running on oeis4.)