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 A378994 #11 Dec 14 2024 14:40:40
%S A378994 1,1,6,1,2,4,2,1,3,2,2,12,2,28,6,1,2,1,2,10,6,4,2,4,1,2,6,8,2,12,2,1,
%T A378994 6,2,2,3,2,4,6,2,2,28,2,4,18,4,2,12,1,1,6,2,2,4,2,8,6,2,2,120,2,4,6,1,
%U A378994 2,12,2,2,6,28,2,1,2,2,6,4,2,4,2,2,3,2,2,24,2,4,6,4,2,6,14,8,6,4,10,4,2,7,18,5
%N A378994 a(n) = gcd(2*n, sigma(2*n)).
%H A378994 Antti Karttunen, <a href="/A378994/b378994.txt">Table of n, a(n) for n = 1..32769</a>
%H A378994 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.
%F A378994 a(n) = A009194(2*n) = gcd(2*n, A062731(n)).
%F A378994 a(n) = 2*n / A378996(n).
%t A378994 Table[GCD[2n,DivisorSigma[1,2n]],{n,100}] (* _James C. McMahon_, Dec 14 2024 *)
%o A378994 (PARI) A378994(n) = gcd(2*n, sigma(2*n));
%Y A378994 Even bisection of A009194.
%Y A378994 Topmost row of array A355925.
%Y A378994 Cf. A000203, A062731, A378995, A378996.
%Y A378994 Cf. also A336850.
%K A378994 nonn
%O A378994 1,3
%A A378994 _Antti Karttunen_, Dec 13 2024