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 A099340 #6 Sep 20 2023 05:42:24
%S A099340 0,4,53,585,6274,62515,625369,6251231,62504587,625010556,6249958503,
%T A099340 62499878794
%N A099340 Frequency of the hexadecimal 7 in the first 10^n hexadecimal digits of Pi.
%H A099340 Kanada Laboratory, <a href="https://web.archive.org/web/20120324194210/http://pi2.cc.u-tokyo.ac.jp/pi-hexa_current.html">Statistical Distribution Information</a>.
%t A099340 $MaxPrecision = 1100000; ph = Drop[ RealDigits[Pi, 16, 5*10^5] [[1]], 1]; Table[ Count[ Take[ph, 10^n], 7], {n, 5}]
%Y A099340 Cf. A000796, A062964, A099333, A099334, A099335, A099336, A099337, A099338, A099339, A099341, A099342, A099343, A099344, A099345, A099346, A099347, A099348.
%K A099340 base,nonn,more
%O A099340 1,2
%A A099340 _Robert G. Wilson v_, Oct 12 2004