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 A195541 #10 Mar 17 2017 09:31:47
%S A195541 5,12,44,51,280,949,103488,133416,4142957,81015132,141119360,
%T A195541 2339121011,22104171804,658972588452,461228244281,3140753982224,
%U A195541 7467448353120,49702513350325,3912991025369532,130254818350668557,177768662787348689760
%N A195541 Denominators a(n) of Pythagorean approximations b(n)/a(n) to e.
%C A195541 See A195500 for a discussion and references.
%t A195541 r = E; z = 23;
%t A195541 p[{f_, n_}] := (#1[[2]]/#1[[
%t A195541 1]] &)[({2 #1[[1]] #1[[2]], #1[[1]]^2 - #1[[
%t A195541 2]]^2} &)[({Numerator[#1], Denominator[#1]} &)[
%t A195541 Array[FromContinuedFraction[
%t A195541 ContinuedFraction[(#1 + Sqrt[1 + #1^2] &)[f], #1]] &, {n}]]]];
%t A195541 {a, b} = ({Denominator[#1], Numerator[#1]} &)[
%t A195541 p[{r, z}]] (* A195541, A195542 *)
%t A195541 Sqrt[a^2 + b^2] (* A195543 *)
%t A195541 (* _Peter J. C. Moses_, Sep 02 2011 *)
%Y A195541 Cf. A195500, A195542, A195543.
%K A195541 nonn
%O A195541 1,1
%A A195541 _Clark Kimberling_, Sep 20 2011