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A343225 Primitive terms of A343218. Numbers k such that A343220(k) = 1.

%I A343225 #6 May 03 2021 18:39:21
%S A343225 3,7,10,11,17,19,20,23,26,27,29,31,32,40,43,45,47,52,53,59,65,67,71,
%T A343225 72,74,79,80,82,83,89,98,103,104,107,117,122,125,127,128,131,139,146,
%U A343225 148,149,151,162,163,164,167,179,185,191,194,196,197,199,200,202,205,208,211,218,223,226,227,233,239,243,244,245,251
%N A343225 Primitive terms of A343218. Numbers k such that A343220(k) = 1.
%C A343225 For any term x, and for any y > 0, if gcd(x,y) = 1, then x*y is included in A343218.
%o A343225 (PARI)
%o A343225 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
%o A343225 A343219(n) = (A003415(sigma(n))>n);
%o A343225 A343220(n) = sumdiv(n,d,if(1==gcd(d,n/d),A343219(d),0));
%o A343225 isA343225(n) = (1==A343220(n));
%Y A343225 Positions of 1's in A343220.
%Y A343225 Subsequence of A343218.
%Y A343225 Cf. A000203, A003415, A343219.
%K A343225 nonn
%O A343225 1,1
%A A343225 _Antti Karttunen_, Apr 09 2021