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 A375526 #14 Aug 31 2024 08:32:11
%S A375526 2,6,30,210,420,420,1260,126,3150,97650,830025,6640200,6640200,
%T A375526 312089400,312089400,9050592600,72404740800,4851117633600,
%U A375526 354131587252800,4603710634286400,4603710634286400,197959557274315200,15227658251870400,1477082850431428800,78285391072865726400
%N A375526 a(n) = denominator of Sum_{i=1..n} 1/A031216(i).
%H A375526 Alois P. Heinz, <a href="/A375526/b375526.txt">Table of n, a(n) for n = 1..882</a>
%e A375526 The first few fractions are 1/2, 5/6, 31/30, 247/210, 529/420, 559/420, 1747/1260, 181/126, 4651/3150, 147331/97650, 1276726/830025, 10379813/6640200, 10527373/6640200, ...
%p A375526 b:= n-> (l-> add(l[i]*11^(i-1), i=1..nops(l)))(convert(ithprime(n),base,10)):
%p A375526 g:= proc(n) option remember; `if`(n<1, 0, g(n-1)+1/b(n)) end:
%p A375526 a:= n-> denom(g(n)):
%p A375526 seq(a(n), n=1..25); # _Alois P. Heinz_, Aug 30 2024
%o A375526 (PARI) a(n) = denominator(sum(i=1, n, 1/fromdigits(digits(prime(i)), 11))); \\ _Michel Marcus_, Aug 31 2024
%Y A375526 Cf. A031216, A375525.
%K A375526 nonn,frac
%O A375526 1,1
%A A375526 _N. J. A. Sloane_, Aug 30 2024