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%I #12 Dec 07 2016 10:34:49
%S 5,260,7020,94635,5103280,137599280,1855038645,100034487540,
%T 2697221086300,36362467421275,1960876019662560,52870927596046560,
%U 712777084536797285,38437091637391006820,1036375920040483589580,13971856374727832955915
%N Denominators a(n) of Pythagorean approximations b(n)/a(n) to 5/2.
%C See A195500 for a discussion and references.
%t r = 5/2; z = 18;
%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}]] (* A195553, A195554 *)
%t Sqrt[a^2 + b^2] (* A195555 *)
%t (* _Peter J. C. Moses_, Sep 02 2011 *)
%Y Cf. A195500, A195554, A195555.
%K nonn,frac
%O 1,1
%A _Clark Kimberling_, Sep 21 2011
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