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 A377878 #12 Nov 16 2024 10:20:10
%S A377878 1,4823,8267,9553,15623,15833,15929,20633,23393,28417,33079,34027,
%T A377878 36941,37129,37939,42599,43249,44431,47291,49374,60097,65832,66323,
%U A377878 69287,69749,70613,74063,74281,74333,74999,77231,83881,86191,86551,87776,88727,99683,106481,108673,111366,113922,115729,118517,124841,126054,129337
%N A377878 Numbers k for which A276085(k) is a multiple of 3125, where A276085 is fully additive with a(p) = p#/p.
%C A377878 A multiplicative semigroup; if m and n are in the sequence then so is m*n.
%C A377878 Question: Does this sequence have asymptotic density? See also questions in A377872 and A377869.
%H A377878 Antti Karttunen, <a href="/A377878/b377878.txt">Table of n, a(n) for n = 1..15711</a>
%H A377878 <a href="/index/Pri#primorial_numbers">Index entries for sequences related to primorial numbers</a>
%F A377878 {k such that Sum e*A377877(A000720(p)-1) == 0 (mod 5^5), when k = Product(p^e)}.
%o A377878 (PARI) isA377878(n) = { my(m=5^5, f = factor(n), pr=1, i=1, s=0); for(k=1, #f~, while(i <= primepi(f[k, 1])-1, pr *= Mod(prime(i),m); i++); s += f[k, 2]*pr); (0==lift(s)); };
%Y A377878 Cf. A000720, A276085, A377869, A377877.
%Y A377878 Subsequence of A373140, and of A377873.
%Y A377878 Cf. also A377872.
%K A377878 nonn
%O A377878 1,2
%A A377878 _Antti Karttunen_, Nov 13 2024