login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

a(n) = A328571(A108951(n)).
7

%I #16 Apr 04 2022 15:26:10

%S 2,3,5,3,7,5,11,15,35,7,13,5,17,11,7,15,19,35,23,7,11,13,29,35,77,17,

%T 55,11,31,77,37,21,13,19,143,35,41,23,17,77,43,143,47,13,77,29,53,35,

%U 2431,77,19,17,59,55,221,11,23,31,61,77,67,37,143,21,323,13,71,19,29,143,73,385,79,41,1001,23,221,17,83,77,385

%N a(n) = A328571(A108951(n)).

%C All terms are squarefree (in A005117). - _Antti Karttunen_, Apr 03 2022

%H Antti Karttunen, <a href="/A346091/b346091.txt">Table of n, a(n) for n = 1..10201</a>

%H <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>

%H <a href="/index/Pri#primorial_numbers">Index entries for sequences related to primorial numbers</a>

%F a(n) = A328571(A108951(n)) = A007947(A276086(A108951(n))).

%F a(n) = A324886(n) / A344592(n).

%F For all n >= 1, a(A000040(n)) = A000040(1+n).

%o (PARI)

%o A002110(n) = prod(i=1,n,prime(i));

%o A108951(n) = { my(f=factor(n)); prod(i=1, #f~, A002110(primepi(f[i, 1]))^f[i, 2]) };

%o A328571(n) = { my(m=1, p=2); while(n, m *= (p^!!(n%p)); n = n\p; p = nextprime(1+p)); (m); };

%o A346091(n) = A328571(A108951(n));

%Y Cf. A000040, A002110, A005117, A007947, A108951, A276086, A324886, A328571, A344592, A346093 [= A276085(a(n))], A351955 (rgs-transform).

%K nonn

%O 1,1

%A _Antti Karttunen_, Jul 09 2021