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%I #9 Mar 11 2014 20:32:49
%S 4,3,204,280,2280,12596,12797,831996,1149440,9341440,51622404,
%T 52441603,3409523404,4710402840,38281220840,211548594996,214905676797,
%U 13972226073596,19303229690880,156876433658880,866926090675204,880683411072003
%N Denominators a(n) of Pythagorean approximations b(n)/a(n) to 5/4.
%C See A195500 for a discussion and references.
%t r = 5/4; z = 26;
%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}]] (* A195565, A195566 *)
%t Sqrt[a^2 + b^2] (* A195567 *)
%t (* by _Peter J. C. Moses_, Sep 02 2011 *)
%Y Cf. A195500, A195566, A195567.
%K nonn
%O 1,1
%A _Clark Kimberling_, Sep 21 2011
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