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 A195550 #10 Dec 07 2016 10:34:25
%S A195550 3,60,660,3597,78480,856080,4669203,101866380,1111191780,6060621597,
%T A195550 132222483360,1442326073760,7866682164003,171624681534300,
%U A195550 1872138132549300,10210947388253997,222768704409038640,2430033853722917040
%N A195550 Denominators a(n) of Pythagorean approximations b(n)/a(n) to 3/2.
%C A195550 See A195500 for a discussion and references.
%t A195550 r = 3/2; z = 21;
%t A195550 p[{f_, n_}] := (#1[[2]]/#1[[
%t A195550 1]] &)[({2 #1[[1]] #1[[2]], #1[[1]]^2 - #1[[
%t A195550 2]]^2} &)[({Numerator[#1], Denominator[#1]} &)[
%t A195550 Array[FromContinuedFraction[
%t A195550 ContinuedFraction[(#1 + Sqrt[1 + #1^2] &)[f], #1]] &, {n}]]]];
%t A195550 {a, b} = ({Denominator[#1], Numerator[#1]} &)[
%t A195550 p[{r, z}]] (* A195550, A195551 *)
%t A195550 Sqrt[a^2 + b^2] (* A195552 *)
%t A195550 (* _Peter J. C. Moses_, Sep 02 2011 *)
%Y A195550 Cf. A195500, A195551, A195552.
%K A195550 nonn,frac
%O A195550 1,1
%A A195550 _Clark Kimberling_, Sep 21 2011