

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



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

1,4


COMMENTS

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.


LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384


MATHEMATICA

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


PROG

(PARI)
A006530(n) = if(1==n, n, vecmax(factor(n)[, 1]));
A179953(n) = { my(q = A006530(n), m = q, k=1); while(m < n, m *= q; k++); k; }; \\ Antti Karttunen, Oct 20 2017


CROSSREFS

Cf. A006530.
Sequence in context: A116479 A318322 A122810 * A277013 A305822 A086436
Adjacent sequences: A179950 A179951 A179952 * A179954 A179955 A179956


KEYWORD

easy,nonn


AUTHOR

Dylan Hamilton, Aug 03 2010


EXTENSIONS

a(1) = 1 prepended and definition rewritten by Antti Karttunen, Oct 20 2017


STATUS

approved



