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 A334491 #24 Sep 08 2022 08:46:25
%S A334491 1,1,1,1,1,6,1,1,1,2,1,24,1,2,3,1,1,18,1,4,1,2,1,288,1,2,1,56,1,216,1,
%T A334491 1,3,2,1,72,1,2,1,40,1,72,1,8,9,2,1,1152,1,2,3,4,1,108,1,448,1,2,1,
%U A334491 20736,1,2,1,1,1,216,1,4,3,8,1,2592,1,2,3,8,1,72
%N A334491 a(n) = Product_{d|n} gcd(d, sigma(d)).
%H A334491 Antti Karttunen, <a href="/A334491/b334491.txt">Table of n, a(n) for n = 1..16384</a>
%F A334491 a(p) = 1 for p = primes (A000040).
%F A334491 a(n) = Product_{d|n} A009194(d). - _Antti Karttunen_, May 09 2020
%e A334491 a(6) = gcd(1, sigma(1)) * gcd(2, sigma(2)) * gcd(3, sigma(3)) * gcd(6, sigma(6)) = gcd(1, 1) * gcd(2, 3) * gcd(3, 4) * gcd(6, 12) = 1 * 1 * 1 * 6 = 6.
%t A334491 a[n_] := Product[GCD[d, DivisorSigma[1, d]], {d, Divisors[n]}]; Array[a, 80] (* _Amiram Eldar_, May 03 2020 *)
%o A334491 (Magma) [&*[GCD(d, &+Divisors(d)): d in Divisors(n)]: n in [1..100]]
%o A334491 (PARI) a(n) = my(d=divisors(n)); prod(k=1, #d, gcd(d[k], sigma(d[k]))); \\ _Michel Marcus_, May 03-11 2020
%Y A334491 Cf. A334490 (Sum_{d|n} gcd(d, sigma(d))), A007955 (pod(n) = Product_{d|n} gcd(d, pod(d))).
%Y A334491 Cf. A000040, A000203 (sigma(n)), A009194.
%K A334491 nonn
%O A334491 1,6
%A A334491 _Jaroslav Krizek_, May 03 2020