cp's OEIS Frontend

A355442 a(n) = gcd(A003961(n), A276086(n)), where A003961 is fully multiplicative with a(p) = nextprime(p), and A276086 is primorial base exp-function.

%I A355442 #15 Jul 18 2022 16:38:52
%S A355442 1,3,1,9,1,5,1,3,5,3,1,5,1,3,5,9,1,25,1,3,5,3,1,5,1,3,125,9,1,7,1,3,1,
%T A355442 3,7,5,1,3,5,63,1,5,1,3,175,3,1,5,1,21,5,9,1,125,7,3,5,3,1,7,1,3,1,9,
%U A355442 7,5,1,3,5,21,1,25,1,3,245,9,1,5,1,21,125,3,1,5,7,3,5,9,1,7,1,3,1,3,7,5,1,3,5,441
%N A355442 a(n) = gcd(A003961(n), A276086(n)), where A003961 is fully multiplicative with a(p) = nextprime(p), and A276086 is primorial base exp-function.
%H A355442 Antti Karttunen, <a href="/A355442/b355442.txt">Table of n, a(n) for n = 1..11550</a>
%H A355442 Antti Karttunen, <a href="/A355442/a355442.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%H A355442 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A355442 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%F A355442 a(n) = gcd(A003961(n), A276086(n)).
%o A355442 (PARI)
%o A355442 A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
%o A355442 A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
%o A355442 A355442(n) = gcd(A003961(n), A276086(n));
%Y A355442 Cf. A003961, A020639, A276086, A355001 [smallest prime factor of a(n)], A355456 [= gcd(sigma(n), a(n))], A355692 (Dirichlet inverse), A355820, A355821 (positions of 1's).
%Y A355442 Cf. also A322361, A324198, A351459.
%K A355442 nonn
%O A355442 1,2
%A A355442 _Antti Karttunen_, Jul 13 2022