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 A380527 #23 Feb 17 2025 14:28:22
%S A380527 1,2,6,7,8,30,36,210,2310,2340,2520,2556,30030,30240,32340,510510,
%T A380527 510720,540540,9699690,9699720,9702000,9729720,10210200,223092870,
%U A380527 223092900,223093080,223095180,232792560,6469693230,6469693236,6469693440,6469695540,6692786100
%N A380527 Numbers k such that k is a multiple of A327860(k), where A327860 is the arithmetic derivative of the primorial base exp-function.
%C A380527 It is conjectured that only terms of A276156 occur here. If any term of A177711 is included, then it must be one of the terms of A381037.
%C A380527 a(34) > A143293(10).
%H A380527 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>.
%o A380527 (PARI)
%o A380527 A327860(n) = { my(s=0, m=1, p=2, e); while(n, e = (n%p); m *= (p^e); s += (e/p); n = n\p; p = nextprime(1+p)); (s*m); };
%o A380527 is_A380527(n) = !(n%A327860(n));
%Y A380527 Cf. A003415, A053669, A143293, A276086, A327860.
%Y A380527 Subsequence of A381035. Conjectured to be a subsequence of A276156.
%Y A380527 Subsequences: A002110, A328110.
%Y A380527 Cf. also A177711, A351087, A381037.
%K A380527 nonn,more
%O A380527 1,2
%A A380527 _Antti Karttunen_, Feb 11 2025