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 A083643 #18 Feb 16 2025 08:32:49
%S A083643 762,763,764,17988,19437,19446,19447,22753,31900,42095,56988,56989,
%T A083643 81293,120564,140953,161862,161863,177122,182604,191104,193034,193035,
%U A083643 193036,204198,210140,211794,220507,220568,220569,224317,235425,235775
%N A083643 Starting positions of strings of four 9's in the decimal expansion of Pi.
%H A083643 Harvey P. Dale, <a href="/A083643/b083643.txt">Table of n, a(n) for n = 1..1000</a>
%H A083643 <a href="/index/Ph#Pi314">Index entries for sequences related to the number Pi</a>
%H A083643 Dave Andersen, <a href="http://www.angio.net/pi/piquery">Pi-Search Page</a>
%H A083643 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PiDigits.html">Pi Digits.</a>
%t A083643 Transpose[StringPosition[StringDrop[ToString[N[Pi,9! ]],2],"9999"]][[1]] (* _Vladimir Joseph Stephan Orlovsky_, Jun 19 2009 *)
%t A083643 Module[{digs=240000,p},p=RealDigits[Pi,10,digs][[1]];SequencePosition[p,{9,9,9,9}][[All,1]]-1] (* _Harvey P. Dale_, Jan 12 2023 *)
%Y A083643 Cf. A083642 (three 9's), A083644 (five 9's).
%K A083643 base,nonn
%O A083643 1,1
%A A083643 _Rick L. Shepherd_, May 05 2003