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Numbers n such that square of largest prime dividing n does not divide n.
31

%I #26 Oct 05 2020 12:26:32

%S 2,3,5,6,7,10,11,12,13,14,15,17,19,20,21,22,23,24,26,28,29,30,31,33,

%T 34,35,37,38,39,40,41,42,43,44,45,46,47,48,51,52,53,55,56,57,58,59,60,

%U 61,62,63,65,66,67,68,69,70,71,73,74,76,77,78,79,80,82,83,84,85

%N Numbers n such that square of largest prime dividing n does not divide n.

%C Numbers n such that the exponent of the largest prime dividing n is one. - _Harvey P. Dale_, May 02 2019

%C From _Peter Munn_, Sep 30 2020: (Start)

%C 2 together with numbers on the left half of the Doudna sequence tree depicted in _Antti Karttunen_'s 2014 comment in A005940.

%C This sequence and A335738, considered as sets, are related by the self-inverse function A225546(.), which maps the members of either set 1:1 onto the other set.

%C (End)

%H Rémy Sigrist, <a href="/A102750/b102750.txt">Table of n, a(n) for n = 1..25000</a>

%e 63 is included because 63 = 3^2 *7 and 7 (the largest prime dividing 63) only divides 63 once.

%t Select[Range[2,100],FactorInteger[#][[-1,2]]==1&] (* _Harvey P. Dale_, May 02 2019 *)

%o (PARI) isok(n) = my(f = factor(n)); n % f[#f~, 1]^2; \\ _Michel Marcus_, May 20 2014

%Y Cf. A070003 (complement, apart from the term 1 that is in neither sequence).

%Y Related to A335738 via A225546.

%Y Cf. A005940.

%K nonn

%O 1,1

%A _Leroy Quet_, Feb 09 2005

%E More terms from _Erich Friedman_, Aug 08 2005