cp's OEIS Frontend

A353763 a(n) = A353750(n) / gcd(A353749(n), A353750(n)).

%I A353763 #9 May 12 2022 16:13:24
%S A353763 1,4,1,15,1,2,2,12,11,2,4,15,5,8,1,435,3,22,4,5,2,24,8,6,29,10,1,2,12,
%T A353763 2,8,45,4,9,4,165,17,16,5,6,3,8,10,12,11,48,16,435,204,58,3,175,36,4,
%U A353763 4,8,4,72,48,5,29,32,11,7119,5,24,208,45,8,8,48,66,31,34,29,20,16,10,16,145,2695,18,120,2,3,40
%N A353763 a(n) = A353750(n) / gcd(A353749(n), A353750(n)).
%C A353763 Denominator of ratio A353749(n) / A353750(n).
%H A353763 Antti Karttunen, <a href="/A353763/b353763.txt">Table of n, a(n) for n = 1..10000</a>
%H A353763 Antti Karttunen, <a href="/A353763/a353763.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%H A353763 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A353763 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A353763 a(n) = A353750(n) / A353761(n) = A353750(n) / gcd(A353749(n), A353750(n)).
%o A353763 (PARI)
%o A353763 A064989(n) = { my(f=factor(n>>valuation(n,2))); for(i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f); };
%o A353763 A353749(n) = (eulerphi(n)*A064989(n));
%o A353763 A353763(n) = { my(s=sigma(n), u=A353749(s)); (u / gcd(A353749(n), u)); };
%Y A353763 Cf. A000010, A000203, A006872, A062401, A064989, A336549, A336550, A353757, A353761, A353762 (numerators), A353765 (positions of 1's).
%K A353763 nonn,frac
%O A353763 1,2
%A A353763 _Antti Karttunen_, May 10 2022