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 A368641 #5 Jan 01 2024 22:28:49
%S A368641 0,0,0,1,3,4,8,9,14,17,23,21,32,34,40,43,55,53,68,67,79,87,99,92,114,
%T A368641 120,129,132,152,145,171,169,187,197,209,203,236,240,253,251,283,274,
%U A368641 308,307,322,341,363,347,389,392,415,421,452,443,477,475,507,522,547,522
%N A368641 a(n) = Sum_{k=2..n} pi(k-1) * (ceiling(n/k) - floor(n/k)).
%F A368641 a(n) = A368612(n) - A368613(n).
%F A368641 a(n) = A368616(n) - A048865(n).
%t A368641 Table[Sum[PrimePi[k - 1] (Ceiling[n/k] - Floor[n/k]), {k, 2, n}], {n, 100}]
%Y A368641 Cf. A000720 (pi), A046992, A048865, A092494, A368610, A368611, A368612, A368613, A368616.
%K A368641 nonn,easy
%O A368641 1,5
%A A368641 _Wesley Ivan Hurt_, Jan 01 2024