cp's OEIS Frontend

A326194 Number of iterations of x -> A009194(x) needed to reach a fixed point when starting from x = n, where A009194(x) = gcd(x, sigma(x)).

%I A326194 #10 Aug 24 2019 11:57:56
%S A326194 0,1,1,1,1,0,1,1,1,2,1,2,1,2,2,1,1,2,1,2,1,2,1,3,1,2,1,0,1,1,1,1,2,2,
%T A326194 1,1,1,2,1,3,1,1,1,2,2,2,1,2,1,1,2,2,1,1,1,2,1,2,1,3,1,2,1,1,1,1,1,2,
%U A326194 2,2,1,2,1,2,1,2,1,1,1,2,1,2,1,1,1,2,2,2,1,3,2,2,1,2,2,3,1,1,2,1,1,1,1,2,2
%N A326194 Number of iterations of x -> A009194(x) needed to reach a fixed point when starting from x = n, where A009194(x) = gcd(x, sigma(x)).
%H A326194 Antti Karttunen, <a href="/A326194/b326194.txt">Table of n, a(n) for n = 1..65537</a>
%F A326194 If gcd(n,sigma(n)) = n, then a(n) = 0, otherwise a(n) = 1 + a(gcd(n,sigma(n))).
%F A326194 a(n) < A326196(n).
%o A326194 (PARI) A326194(n) = { my(u=gcd(n,sigma(n))); if(u==n,0,1+A326194(u)); };
%Y A326194 Cf. A000203, A007691 (positions of zeros), A009194, A326195, A326196.
%K A326194 nonn
%O A326194 1,10
%A A326194 _Antti Karttunen_, Aug 24 2019