A336850 - OEIS

%I #14 Aug 06 2020 23:28:31

%S 1,1,1,1,1,3,1,1,1,1,1,3,1,3,1,1,1,1,1,1,1,1,1,15,1,3,1,3,1,3,1,1,1,1,

%T 1,1,1,3,1,1,1,3,1,13,1,3,1,3,1,3,5,9,1,3,7,3,1,1,1,3,1,1,1,1,1,3,1,1,

%U 5,3,1,5,1,3,1,3,1,3,1,1,1,1,1,9,1,3,1,1,1,1,1,3,1,3,1,3,1,1,1,3,1,15,1,9,1

%N a(n) = gcd(A003961(n), sigma(A003961(n))), where A003961 is the prime shift towards larger primes.

%H Antti Karttunen, <a href="/A336850/b336850.txt">Table of n, a(n) for n = 1..16384</a>

%H Antti Karttunen, <a href="/A336850/a336850.txt">Data supplement: n, a(n) computed for n = 1..65537</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%F a(n) = gcd(A003961(n), A003973(n)) = gcd(A003961(n), A336851(n)).

%F a(n) = A009194(A003961(n)).

%F a(n) = A003961(n) / A336849(n).

%o (PARI) A336850(n) = gcd(A003961(n),sigma(A003961(n)));

%Y Cf. A003961, A003973, A009194, A336849, A336851.

%K nonn

%O 1,6

%A _Antti Karttunen_, Aug 05 2020