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 A348928 #14 Feb 06 2022 15:01:55 %S A348928 1,1,1,1,1,2,1,1,1,2,1,2,1,2,1,1,1,2,1,4,3,2,1,2,1,2,1,2,1,2,1,1,1,2, %T A348928 1,4,1,2,3,4,1,6,1,2,1,2,1,2,1,2,1,4,1,2,5,2,3,2,1,4,1,2,3,1,1,2,1,4, %U A348928 1,2,1,4,1,2,1,2,1,6,1,4,1,2,1,12,1,2,1,2,1,2,1,2,3,2,1,2,1,2,1,4,1,2,1,4,3 %N A348928 a(n) = gcd(n, A003958(n)), where A003958 is multiplicative with a(p^e) = (p-1)^e. %H A348928 Antti Karttunen, <a href="/A348928/b348928.txt">Table of n, a(n) for n = 1..65537</a> %F A348928 a(n) = gcd(n, A003958(n)) = gcd(n, A322582(n)) = gcd(A003958(n), A322582(n)). %t A348928 f[p_, e_] := (p - 1)^e; a[n_] := GCD[n, Times @@ f @@@ FactorInteger[n]]; Array[a, 100] (* _Amiram Eldar_, Nov 07 2021 *) %o A348928 (PARI) %o A348928 A003958(n) = if(1==n,n,my(f=factor(n)); for(i=1,#f~,f[i,1]--); factorback(f)); %o A348928 A348928(n) = gcd(n, A003958(n)); %Y A348928 Cf. A003958, A085731, A126865, A322582, A348929, A348998 [= a(A276086(n))]. %Y A348928 Differs from similar A126864 for the first time at n=36, where a(36) = 4, while A126864(36) = 2. %K A348928 nonn,easy %O A348928 1,6 %A A348928 _Antti Karttunen_, Nov 07 2021