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 A072111 #4 Sep 02 2024 17:16:32
%S A072111 1,5,19,61,203,669,2279,7797,27213,96111,343965,1240617,4513763,
%T A072111 16546859,61027965,226454967,844181631,3161518957,11886015725,
%U A072111 44847272299,169747439789,644345294711,2452231140853,9354606971985
%N A072111 Partial sum of pi(k) from k = 1 to 2^n.
%t A072111 s = 0; k = 1; Do[ While [k <= 2^n, s = s + PrimePi[k]; k++ ]; Print[s], {n, 1, 28} ]
%Y A072111 Cf. A000720, A073224.
%K A072111 nonn
%O A072111 1,2
%A A072111 _Robert G. Wilson v_, Jul 30 2002