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 A189967 #10 Sep 08 2022 08:45:56
%S A189967 4,3,1,1,7,3,7,6,9,1,4,8,9,8,9,9,5,9,5,8,0,5,2,5,9,6,7,0,1,3,0,2,6,2,
%T A189967 9,9,7,6,8,3,7,5,8,1,6,5,8,6,3,7,0,8,2,3,2,3,8,5,4,9,4,6,2,4,9,7,2,5,
%U A189967 8,6,9,9,6,4,2,6,3,3,8,5,1,8,2,3,1,8,0,7,9,0,7,0,9,4,6,3,6,6,8,4,2,3,8,6,1,4,7,5,0,8,1,5,7,6,3,1,7,3,0,7
%N A189967 Decimal expansion of (7+sqrt(105))/4, which has periodic continued fractions [4,3,4,1,4,3,4,1...] and [7/2, 1, 7/2, 1, ...].
%C A189967 Let R denote a rectangle whose shape (i.e., length/width) is (7+sqrt(105))/4. This rectangle can be partitioned into squares in a manner that matches the continued fraction [4,3,4,1,4,3,4,1...]. It can also be partitioned into rectangles of shape 3/2 and 3 so as to match the continued fraction [7/2, 1, 7/2, 1, ...]. For details, see A188635.
%H A189967 G. C. Greubel, <a href="/A189967/b189967.txt">Table of n, a(n) for n = 1..10000</a>
%e A189967 4.311737691489899595805259670130262997684...
%t A189967 FromContinuedFraction[{7/2, 1, {7/2, 1}}]
%t A189967 ContinuedFraction[%, 25] (* [4,3,4,1,4,3,4,1...] *)
%t A189967 RealDigits[N[%%, 120]] (* A189968 *)
%t A189967 N[%%%, 40]
%o A189967 (PARI) (7+sqrt(105))/4 \\ _G. C. Greubel_, Jan 12 2018
%o A189967 (Magma) (7+Sqrt(105))/4 // _G. C. Greubel_, Jan 12 2018
%Y A189967 Cf. A188635, A189967.
%K A189967 nonn,cons
%O A189967 1,1
%A A189967 _Clark Kimberling_, May 05 2011