cp's OEIS Frontend

A328479 a(n) = n/A328478(n), where A328478(n) is obtained by repeatedly dividing n by the largest primorial that divides it until a fixed point is reached.

%I A328479 #13 Jan 11 2022 03:21:37
%S A328479 1,2,1,4,1,6,1,8,1,2,1,12,1,2,1,16,1,6,1,4,1,2,1,24,1,2,1,4,1,30,1,32,
%T A328479 1,2,1,36,1,2,1,8,1,6,1,4,1,2,1,48,1,2,1,4,1,6,1,8,1,2,1,60,1,2,1,64,
%U A328479 1,6,1,4,1,2,1,72,1,2,1,4,1,6,1,16,1,2,1,12,1,2,1,8,1,30,1,4,1,2,1,96,1,2,1,4,1,6,1,8,1
%N A328479 a(n) = n/A328478(n), where A328478(n) is obtained by repeatedly dividing n by the largest primorial that divides it until a fixed point is reached.
%C A328479 a(n) is the largest term in A025487 that divides n evenly. - _Hal M. Switkay_, May 04 2021
%H A328479 Antti Karttunen, <a href="/A328479/b328479.txt">Table of n, a(n) for n = 1..30030</a>
%H A328479 <a href="/index/Pri#primorial_numbers">Index entries for sequences related to primorial numbers</a>
%F A328479 a(n) = n / A328478(n).
%t A328479 A111701[n_] := A111701[n] = Block[{m = n, k = 1}, While[IntegerQ[m/Prime[k]], m = m/Prime[k]; k++]; m];
%t A328479 A328478[n_] := If[A111701[n] == n, n, A328478[A111701[n]]];
%t A328479 A328479[n_] := n/A328478[n];
%t A328479 Array[A328479, 105] (* _Jean-François Alcover_, Jan 11 2022, after _Robert G. Wilson v_ in A111701 *)
%o A328479 (PARI)
%o A328479 A111701(n) = forprime(p=2, , if(n%p, return(n), n /= p));
%o A328479 A328478(n) = { my(u=A111701(n)); if(u==n, return(n), return(A328478(u))); };
%o A328479 A328479(n) = (n/A328478(n));
%Y A328479 Cf. A002110, A053589, A111701, A328478.
%K A328479 nonn
%O A328479 1,2
%A A328479 _Antti Karttunen_, Oct 19 2019