This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A355818 #11 Jul 20 2022 08:49:52
%S A355818 1,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,
%T A355818 1,1,1,1,1,5,1,1,1,1,3,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
%U A355818 3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,7,1,1,3,1,1,1,7,1,1,1,1,1,1,1,3,1,1,1,1,1,3
%N A355818 Greatest common divisor of n, sigma(n) and A276086(n), where A276086 is primorial base exp-function.
%H A355818 Antti Karttunen, <a href="/A355818/b355818.txt">Table of n, a(n) for n = 1..65537</a>
%H A355818 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%H A355818 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A355818 a(n) = gcd(n, A324644(n)) = gcd(A000203(n), A324198(n)) = gcd(A009194(n), A276086(n)).
%F A355818 a(n) = gcd(A009194(n), A324198(n)).
%o A355818 (PARI)
%o A355818 A009194(n) = gcd(n, sigma(n));
%o A355818 A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
%o A355818 A355818(n) = gcd(A009194(n), A276086(n));
%Y A355818 Sequence contains only terms of A048103.
%Y A355818 Cf. A000203, A009194, A276086, A324198, A324644.
%Y A355818 Cf. also A355815, A327858, A355456.
%K A355818 nonn
%O A355818 1,15
%A A355818 _Antti Karttunen_, Jul 19 2022