cp's OEIS Frontend

A354871 a(n) = gcd(A056239(n), A258851(n)).

%I A354871 #9 Jun 12 2022 22:53:16
%S A354871 0,1,2,2,3,1,4,3,4,1,5,4,6,5,1,4,7,1,8,1,2,3,9,1,6,1,6,2,10,1,11,5,1,
%T A354871 1,1,6,12,1,4,6,13,1,14,1,1,1,15,2,8,1,1,4,16,1,2,1,2,1,17,1,18,1,8,6,
%U A354871 3,1,19,3,1,1,20,1,21,1,4,2,1,1,22,1,8,1,23,4,2,1,4,4,24,1,2,1,1,1,1,1,25,1,3,4
%N A354871 a(n) = gcd(A056239(n), A258851(n)).
%H A354871 Antti Karttunen, <a href="/A354871/b354871.txt">Table of n, a(n) for n = 1..65537</a>
%H A354871 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F A354871 a(n) = gcd(A056239(n), A258851(n)).
%F A354871 a(n) = gcd(A056239(n), A278510(n)) = gcd(A258851(n), A278510(n)).
%F A354871 For n > 1, a(n) = A056239(n) / A354872(n) = A258851(n) / A354873(n).
%o A354871 (PARI)
%o A354871 A056239(n) = { my(f); if(1==n, 0, f=factor(n); sum(i=1, #f~, f[i, 2] * primepi(f[i, 1]))); }
%o A354871 A258851(n) = (n*sum(i=1, #n=factor(n)~, n[2, i]*primepi(n[1, i])/n[1, i])); \\ From A258851
%o A354871 A354871(n) = gcd(A056239(n), A258851(n));
%Y A354871 Cf. A056239, A258851, A278510, A354872, A354873.
%K A354871 nonn
%O A354871 1,3
%A A354871 _Antti Karttunen_, Jun 11 2022