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 A360325 #11 Feb 04 2023 14:14:53
%S A360325 1,1,3,1,5,3,1,1,9,5,11,3,1,1,15,1,17,9,1,5,3,11,1,3,25,1,27,1,1,15,
%T A360325 31,1,33,17,5,9,1,1,3,5,41,3,1,11,45,1,1,3,1,25,51,1,1,27,55,1,3,1,59,
%U A360325 15,1,31,9,1,5,33,67,17,3,5,1,9,1,1,75,1,11,3,1
%N A360325 a(n) is the largest divisor of n that has only prime-indexed prime factors.
%H A360325 Amiram Eldar, <a href="/A360325/b360325.txt">Table of n, a(n) for n = 1..10000</a>
%F A360325 a(n) = 1 if and only if n is in A320628.
%F A360325 a(n) = n if and only if n is in A076610.
%F A360325 a(n) = n/A360329(n).
%F A360325 Multiplicative with a(p^e) = p^e if p is a prime-indexed prime (A006450), and 1 otherwise.
%t A360325 f[p_, e_] := If[PrimeQ[PrimePi[p]], p^e, 1]; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100]
%o A360325 (PARI) a(n) = {my(f = factor(n)); prod(i = 1, #f~, if(isprime(primepi(f[i, 1])), f[i, 1]^f[i, 2], 1)); }
%Y A360325 Cf. A006450, A076610, A320628, A360326, A360327, A360329.
%K A360325 nonn,mult
%O A360325 1,3
%A A360325 _Amiram Eldar_, Feb 03 2023