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 A157216 #14 Feb 11 2025 15:12:50
%S A157216 2,2,9,4,0,0,8,9,0,9,5,8,8,1,6,4,6,3,0,5,9,9,6,4,9,5,2,6,8,5,3,0,8,6,
%T A157216 3,2,8,9,8,7,3,7,5,6,8,4,5,5,4,1,9,9,4,6,4,1,3,0,6,6,5,5,2,1,3,0,7,7,
%U A157216 8,0,4,6,0,3,0,3,5,7,3,9,6,7,1,2,7,9,9,1,8,1,0,8,7,2,1,7,3,2,9,5,9,5,7,3,0
%N A157216 Decimal expansion of (18 + 5*sqrt(2))/(18 - 5*sqrt(2)).
%C A157216 lim_{n -> infinity} b(n)/b(n-1) = (18+5*sqrt(2))/(18-5*sqrt(2)) for n mod 3 = {1, 2}, b = A129544.
%C A157216 lim_{n -> infinity} b(n)/b(n-1) = (18+5*sqrt(2))/(18-5*sqrt(2)) for n mod 3 = {0, 2}, b = A157213.
%H A157216 G. C. Greubel, <a href="/A157216/b157216.txt">Table of n, a(n) for n = 1..10000</a>
%H A157216 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.
%e A157216 (18 + 5*sqrt(2))/(18 - 5*sqrt(2)) = 2.29400890958816463059...
%t A157216 With[{c=5Sqrt[2]},RealDigits[(18+c)/(18-c),10,120][[1]]] (* _Harvey P. Dale_, Dec 13 2011 *)
%o A157216 (PARI) (18+5*sqrt(2))/(18-5*sqrt(2)) \\ _G. C. Greubel_, Jan 27 2018
%o A157216 (Magma) (18+5*Sqrt(2))/(18-5*Sqrt(2)) // _G. C. Greubel_, Jan 27 2018
%Y A157216 Cf. A129544, A157213, A157214 (decimal expansion of 18+5*sqrt(2)), A157215 (decimal expansion of 18-5*sqrt(2)).
%K A157216 cons,nonn
%O A157216 1,1
%A A157216 _Klaus Brockhaus_, Feb 25 2009