cp's OEIS Frontend

A339969 a(n) = gcd(n, A005940(1+n)).

%I A339969 #8 Dec 25 2020 19:32:16
%S A339969 1,1,1,1,1,1,3,1,1,1,5,1,1,1,1,1,1,1,3,1,5,3,1,1,1,25,1,9,1,1,3,1,1,
%T A339969 11,1,7,1,1,1,1,1,1,21,1,1,45,1,1,1,49,1,1,1,1,9,1,7,1,1,1,5,1,1,1,1,
%U A339969 13,3,1,1,3,1,1,1,1,1,3,1,7,3,1,1,1,1,1,7,5,1,3,11,1,15,1,1,3,1,1,1,1,1,1,5
%N A339969 a(n) = gcd(n, A005940(1+n)).
%H A339969 Antti Karttunen, <a href="/A339969/b339969.txt">Table of n, a(n) for n = 0..16384</a>
%H A339969 Antti Karttunen, <a href="/A339969/a339969.txt">Data supplement: n, a(n) computed for n = 0..65537</a>
%H A339969 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A339969 a(n) = gcd(n, A005940(1+n)).
%o A339969 (PARI)
%o A339969 A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
%o A339969 A339969(n) = gcd(n, A005940(1+n));
%Y A339969 Cf. A005940.
%Y A339969 Cf. also A322361, A324198, A328231.
%K A339969 nonn
%O A339969 0,7
%A A339969 _Antti Karttunen_, Dec 25 2020