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 A250744 #14 Aug 31 2020 16:40:56
%S A250744 1,1,5,17,91,379,721,35849,614893,6800951,607326679,3651532639,
%T A250744 851897554247,24724573280923,301787157353771,14188276949397301,
%U A250744 22662903194758542865,430644772287132696121,1800653989272587268758525,369150309888695460837999593
%N A250744 Denominator of the harmonic mean of the first n positive Fibonacci numbers.
%C A250744 Similar to A059248. - _Michel Marcus_ and _Colin Barker_, Nov 28 2014
%H A250744 Colin Barker, <a href="/A250744/b250744.txt">Table of n, a(n) for n = 1..120</a>
%e A250744 a(4) = 17 because the first 4 positive Fibonacci numbers are [1,1,2,3], and 4/(1/1+1/1+1/2+1/3) = 24/17.
%t A250744 Module[{nn=20,f},f=Fibonacci[Range[nn]];Table[HarmonicMean[Take[f,n]],{n,nn}]]//Denominator (* _Harvey P. Dale_, Aug 31 2020 *)
%o A250744 (PARI) s=vector(30); f=Vec(x/(1-x-x^2)+O(x^(#s+1))); n=d=0; for(k=1, #s, n++; d+=1/f[k]; s[k]=denominator(n/d)); s
%Y A250744 Cf. A000045 (Fibonacci numbers), A250743 (numerators).
%Y A250744 Cf. A059248.
%K A250744 nonn,frac
%O A250744 1,3
%A A250744 _Colin Barker_, Nov 27 2014