A339964 - OEIS

%I #7 Dec 25 2020 19:31:41

%S 1,3,4,1,6,1,8,3,1,1,12,1,14,3,8,1,18,1,20,21,2,1,24,5,1,3,4,1,30,1,

%T 32,3,2,1,12,1,38,3,8,1,42,1,44,3,2,1,48,1,1,3,4,1,54,5,8,3,2,1,60,1,

%U 62,3,8,1,6,1,68,3,2,1,72,1,74,3,4,7,6,1,80,3,1,1,84,1,2,3,8,1,90,13,4,3,2,1,24,1,98,9,4,1,102

%N a(n) = gcd(sigma(n), n+1).

%H Antti Karttunen, <a href="/A339964/b339964.txt">Table of n, a(n) for n = 1..65537</a>

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

%o (PARI) A339964(n) = gcd(sigma(n),n+1);

%Y Cf. A000203, A009194, A339965, A339966.

%Y Cf. A339963 (positions of 2's).

%Y Cf. also A049559, A062754.

%K nonn

%O 1,2

%A _Antti Karttunen_, Dec 25 2020