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%I #11 Mar 11 2014 01:41:27
%S 4,55,1120,2997,35460,3140676,1921787,32412552,58579212,441025780,
%T 410535015,77779347592,654610870027,2025218645520,7961709199049,
%U 29306172663680,88433963478036,109778426942667,2900499582545112,4716082204442140
%N Denominators a(n) of Pythagorean approximations b(n)/a(n) to sqrt(3/4).
%C See A195500 for a discussion and references.
%t r = Sqrt[3/4]; z = 28;
%t p[{f_, n_}] := (#1[[2]]/#1[[
%t 1]] &)[({2 #1[[1]] #1[[2]], #1[[1]]^2 - #1[[
%t 2]]^2} &)[({Numerator[#1], Denominator[#1]} &)[
%t Array[FromContinuedFraction[
%t ContinuedFraction[(#1 + Sqrt[1 + #1^2] &)[f], #1]] &, {n}]]]];
%t {a, b} = ({Denominator[#1], Numerator[#1]} &)[
%t p[{r, z}]] (* A195634, A195635 *)
%t Sqrt[a^2 + b^2] (* A195636 *)
%t (* _Peter J. C. Moses_, Sep 02 2011 *)
%Y Cf. A195500, A195635, A195636.
%K nonn
%O 1,1
%A _Clark Kimberling_, Sep 22 2011