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 A154883 #42 Jul 28 2019 21:43:14
%S A154883 3,7,15,1,292,2,14,84,13,4,6,99,5,8,12,16,161,45,22,24,10,26,42,9,57,
%T A154883 18,19,30,28,20,120,23,21,127,29,11,48,436,58,34,44,20776,94,55,32,50,
%U A154883 43,72,33,27,36,106,17,141,39,125,41,37,25,47,61,376,107,31
%N A154883 Distinct entries in continued fraction for Pi in the order of their appearance.
%C A154883 This is presumably a permutation of the positive integers. The inverse permutation (or "index sequence") A322778 begins 4,6,1,10,13,11,2,14,... and gives the position in the continued fraction of Pi at which 1, 2, 3, 4, 5, 6, ... first appear. - Remark corrected by _N. J. A. Sloane_, Jan 04 2019
%C A154883 The name means that when a number not yet in this sequence appears in the continued fraction of Pi, then that number is added to the sequence. - _T. D. Noe_, May 06 2013
%H A154883 Charles R Greathouse IV, <a href="/A154883/b154883.txt">Table of n, a(n) for n = 1..1000</a>, May 06 2013
%e A154883 Since the actual continued fraction for Pi is 3, 7, 15, 1, 292, 1, 1, 1, 2, ..., this sequence begins 3, 7, 15, 1, 292, 2, ...
%t A154883 DeleteDuplicates[ContinuedFraction[Pi,1000]] (* _Harvey P. Dale_, May 06 2013 *)
%t A154883 t = {}; s = ContinuedFraction[Pi, 1000]; Do[If[! MemberQ[t, s[[n]]], AppendTo[t, s[[n]]]], {n, Length[s]}]; t (* _T. D. Noe_, May 06 2013 *)
%o A154883 (PARI) \p 10000
%o A154883 v=contfrac(Pi); for(i=1,#v,for(j=1,i-1,if(v[i]==v[j],v[i]=0;break))); v=select(n->n,v) \\ _Charles R Greathouse IV_, May 06 2013
%Y A154883 Cf. A001203, A033089 (for records of main continued fraction), A322778 (inverse), A033090.
%K A154883 nice,nonn
%O A154883 1,1
%A A154883 Lee Corbin (lcorbin(AT)rawbw.com), Jan 16 2009
%E A154883 More terms from _Harvey P. Dale_, May 05 2013