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 A369869 #10 Jan 22 2025 14:30:03
%S A369869 0,0,0,2,0,8,0,8,6,17,0,26,0,30,21,32,0,54,0,48,34,57,0,92,15,80,36,
%T A369869 92,0,148,0,96,61,121,43,186,0,154,84,192,0,270,0,184,126,209,0,312,
%U A369869 28,265,125,242,0,369,70,284,158,292,0,520,0,343,204,352,93,557,0
%N A369869 a(n) = n * Sum_{p|n, p prime} pi(n/p) / p.
%H A369869 Antti Karttunen, <a href="/A369869/b369869.txt">Table of n, a(n) for n = 1..20000</a>
%F A369869 a(p^k) = p^(k-1) * pi(p^(k-1)), for prime p and k >= 1. - _Wesley Ivan Hurt_, Jun 26 2024
%t A369869 Table[n*DivisorSum[n, PrimePi[n/#]/# &, PrimeQ[#] &], {n, 100}]
%o A369869 (PARI) A369869(n) = if(1==n, 0, n*my(f=factor(n)); n*sum(i=1, #f~, primepi(n/f[i, 1])/f[i, 1])); \\ _Antti Karttunen_, Jan 22 2025
%Y A369869 Cf. A000720 (pi), A345301, A369745, A369747, A369868.
%K A369869 nonn,easy
%O A369869 1,4
%A A369869 _Wesley Ivan Hurt_, Feb 03 2024