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 A108664 #25 Jul 05 2020 13:42:50
%S A108664 6,7,2,16,8,4,2,1,10,3,4,17,1,20,22,7,15,25,11,7,3,3,6,9,6,33,2,10,25,
%T A108664 10,34,3,5,5,12,3,32,3,8,15,2,2,4,11,7,19,1,5,17,5,9,2,3,26,2,4,9,7,4,
%U A108664 11,8,22,42,3,19,6,11,11,4,3,4,8,1,8,4,14,6,9,1,14,1,1,1,1,1,5,5,1,5,11
%N A108664 In the decimal expansion of Pi, lengths of sublists ending with 9.
%C A108664 Take the decimal expansion of Pi: s={3,1,4,1,5,9,2,6,5,3,5,8,9,7,9,3, 2,3,8,4,6,2,6,4,3,3,8,3,2,7,9,5,0,2,8,8,4}. Split s into sublists each ending with 9: {{3,1,4,1,5,9}, {2,6,5,3,5,8,9}, {7,9}, {3,2,3,8,4,6,2,6,4,3,3,8,3,2,7,9}, {5,0,2,8,8,4,1,9}}. The sequence gives the lengths of the sublists: 6,7,2,16,8,4,2,1,10,3,4,17,1,20,22,7. Cf. A053753 (positions of 9's in the decimal expansion of Pi).
%F A108664 a(n) = A053753(n+1) - A053753(n).
%Y A108664 Cf. A000796, A037007, A053753, A108663, A139727, A014974.
%K A108664 base,nonn
%O A108664 1,1
%A A108664 _Zak Seidov_, Jun 17 2005