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 A010170 #32 Nov 15 2023 01:16:08
%S A010170 9,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,
%T A010170 18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,1,18,
%U A010170 1,18,1,18,1,18,1,18,1,18,1
%N A010170 Continued fraction for sqrt(99).
%H A010170 Harry J. Smith, <a href="/A010170/b010170.txt">Table of n, a(n) for n = 0..20000</a>
%H A010170 G. Xiao, <a href="http://wims.unice.fr/~wims/en_tool~number~contfrac.en.html">Contfrac</a>.
%H A010170 <a href="/index/Con#confC">Index entries for continued fractions for constants</a>.
%H A010170 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F A010170 a(n+1) = 18^n mod 19, for all n >= 0. - _M. F. Hasler_, Mar 10 2011
%F A010170 From _Amiram Eldar_, Nov 14 2023: (Start)
%F A010170 Multiplicative with a(2^e) = 18, and a(p^e) = 1 for an odd prime p.
%F A010170 Dirichlet g.f.: zeta(s) * (1 + 17/2^s). (End)
%e A010170 9.9498743710661995473447982... = 9 + 1/(1 + 1/(18 + 1/(1 + 1/(18 + ...)))). - _Harry J. Smith_, Jun 12 2009
%t A010170 ContinuedFraction[Sqrt[99],300] (* _Vladimir Joseph Stephan Orlovsky_, Mar 10 2011 *)
%t A010170 PadRight[{9},120,{18,1}] (* _Harvey P. Dale_, Aug 30 2021 *)
%o A010170 (PARI) { allocatemem(932245000); default(realprecision, 27000); x=contfrac(sqrt(99)); for (n=0, 20000, write("b010170.txt", n, " ", x[n+1])); } \\ _Harry J. Smith_, Jun 12 2009
%Y A010170 Cf. A010550 (decimal expansion).
%K A010170 nonn,cofr,easy,mult
%O A010170 0,1
%A A010170 _N. J. A. Sloane_