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 A064857 #16 Jan 31 2025 03:33:20
%S A064857 1,3,5,7,53,107,25,1501,563,901,12389,16519,322121,644243,53687,
%T A064857 1288489,3650719,4380863,18917363,3557111,104045497,416181989,
%U A064857 2393046437,455818369,23930464373,47860928747,10255913303,11044829711
%N A064857 Numerators of partial sums of reciprocals of lcm(1..n) = A003418(n).
%H A064857 Robert Israel, <a href="/A064857/b064857.txt">Table of n, a(n) for n = 1..2296</a>
%F A064857 a(n) = numerator(Sum_{j=1..n} 1/lcm(1..n)).
%e A064857 n = 7: LCM values: 1, 2, 6, 12, 60, 60, 420; partial sum = 1 + 1/2 + 1/6 + 1/12 + 1/60 + 1/60 + 1/420 = (420 + 210 + 70 + 35 + 7 + 7 + 1)/420 = 750/420 = 25/14, so a(7) = 25.
%p A064857 R:= 1: m:= 1: for n from 2 to 100 do m:= ilcm(m,n); R:= R,1/m od:
%p A064857 P:= ListTools:-PartialSums([R]):
%p A064857 map(numer,P); # _Robert Israel_, Jan 30 2025
%t A064857 q[x_] := Apply[LCM, Table[j, {j, 1, x}]] Table[Numerator[Apply[Plus, Table[1/q[w], {w, 1, m}]]], {m, 1, 30}]
%t A064857 Accumulate[Table[1/LCM@@Range[n],{n,30}]]//Numerator (* _Harvey P. Dale_, Aug 08 2021 *)
%Y A064857 Cf. A003418, A064858, A064859.
%K A064857 nonn,frac
%O A064857 1,2
%A A064857 _Labos Elemer_, Oct 08 2001