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 A324394 #10 Mar 05 2019 18:19:28 %S A324394 1,1,1,1,1,6,1,1,1,2,3,4,1,3,1,1,1,2,1,2,1,6,3,12,1,1,1,1,1,6,1,1,1,2, %T A324394 3,28,1,6,1,10,1,2,3,12,1,18,15,4,1,1,3,1,1,6,1,3,1,2,3,4,1,3,1,1,1,2, %U A324394 1,4,1,6,3,8,7,2,3,28,1,6,1,2,1,2,3,28,1,6,3,120,1,2,1,6,1,90,3,12,1,1,1,7,1,6,3,5,7,2 %N A324394 a(n) = A009194(A005940(1+n)), where A005940 is the Doudna sequence and A009194(n) = gcd(n,sigma(n)). %H A324394 Antti Karttunen, <a href="/A324394/b324394.txt">Table of n, a(n) for n = 0..16384</a> %H A324394 Antti Karttunen, <a href="/A324394/a324394.txt">Data supplement: n, a(n) computed for n = 0..65537</a> %H A324394 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %H A324394 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %F A324394 a(n) = A009194(A005940(1+n)) = gcd(A005940(1+n), A324054(n)). %o A324394 (PARI) A324394(n) = { my(m1=1,m2=1,p=2,mp=p*p); while(n, if(!(n%2), p=nextprime(1+p); mp = p*p, m1 *= p; if(3==(n%4),mp *= p,m2 *= (mp-1)/(p-1))); n>>=1); gcd(m1,m2); }; %o A324394 (PARI) %o A324394 A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ From A005940 %o A324394 A009194(n) = gcd(n, sigma(n)); %o A324394 A324394(n) = A009194(A005940(1+n)); %Y A324394 Cf. A009194, A324054, A324055, A324058, A324349, A324395. %K A324394 nonn %O A324394 0,6 %A A324394 _Antti Karttunen_, Mar 05 2019