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 A328241 #10 May 31 2024 09:22:51
%S A328241 0,8,13,16,18,19,20,21,22,23,24,25,26,27,28,29,31,36,44,45,48,49,50,
%T A328241 51,52,53,54,55,56,57,58,59,64,70,72,78,79,80,81,82,83,84,85,86,87,88,
%U A328241 89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121
%N A328241 Numbers n for which A327860(n) = A003415(A276086(n)) is not a squarefree number.
%H A328241 Antti Karttunen, <a href="/A328241/b328241.txt">Table of n, a(n) for n = 1..20000</a>
%H A328241 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%o A328241 (PARI)
%o A328241 A327860(n) = { my(m=1, i=0, s=0, pr=1, nextpr); while((n>0), i=i+1; nextpr = prime(i)*pr; if((n%nextpr), my(e=((n%nextpr)/pr)); m *= (prime(i)^e); s += (e / prime(i)); n-=(n%nextpr)); pr=nextpr); (s*m); };
%o A328241 isA328241(n) = !issquarefree(A327860(n));
%Y A328241 Cf. A003415, A008966, A276086, A327860.
%Y A328241 Cf. A328242 (complement).
%K A328241 nonn
%O A328241 1,2
%A A328241 _Antti Karttunen_, Oct 10 2019