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 A327979 #10 Oct 04 2019 23:30:14 %S A327979 1,1,1,2,1,2,1,2,3,2,1,2,1,2,1,4,1,6,1,4,3,2,1,2,5,2,9,2,1,2,1,8,1,2, %T A327979 1,6,1,2,3,4,1,6,1,2,3,2,1,4,7,10,1,4,1,18,5,2,3,2,1,4,1,2,3,16,1,2,1, %U A327979 4,1,2,1,6,1,2,5,2,1,6,1,4,27,2,1,6,1,2,1,2,1,6,1,2,3,2,1,8,1,14,3,20,1,2,1,4,3 %N A327979 a(n) = gcd(n, A002322(n)), where A002322 is Carmichael lambda, also known as psi. %H A327979 Antti Karttunen, <a href="/A327979/b327979.txt">Table of n, a(n) for n = 1..65537</a> %F A327979 a(n) = gcd(n, A002322(n)). %t A327979 Array[GCD[#, CarmichaelLambda[#]] &, 100] (* _Amiram Eldar_, Oct 04 2019 *) %o A327979 (PARI) A327979(n) = gcd(n, lcm(znstar(n)[2])); %Y A327979 Cf. A002322. %Y A327979 Cf. also A009191, A009194, A009195, A306695. %K A327979 nonn %O A327979 1,4 %A A327979 _Antti Karttunen_, Oct 04 2019