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 A091657 #6 Aug 05 2024 14:54:42
%S A091657 4,9,9,30,40,40,40,44,130,130,276,276,276,276,276,276,647,647,647,647,
%T A091657 647,647,647,647,791,791,791,791,791,791,878,878,878,878,1008,1008,
%U A091657 1008,3041,3041,3041,3041,3041,3041,3041,3041,3200,3200,3200,3200,3200,3200
%N A091657 Length of the smallest prefix of the continued fraction expansion for Pi that includes each of 1..n.
%F A091657 a(n) = max(A032523(n), a(n-1)) for n > 1. - _Andrew Howroyd_, Aug 05 2024
%t A091657 f[n_] := Block[{k = 1}, While[ StringPosition[ ToString[ Union[ ContinuedFraction[Pi, k]]], StringDrop[ ToString[ Table[i, {i, n}]], -1]] == {}, k++ ]; k]; Table[ f[n], {n, 1, 51}]
%Y A091657 Cf. A001203, A032523.
%K A091657 nonn
%O A091657 1,1
%A A091657 _Robert G. Wilson v_, Jan 26 2004
%E A091657 Name clarified by _Andrew Howroyd_, Aug 05 2024