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 A126147 #25 Sep 21 2018 11:08:56
%S A126147 0,0,1,4,19,177,1766,26868,421725,7692857,208699781,5420553787,
%T A126147 180993613044,7075587523888,278356624078085,11601694011103611,
%U A126147 552358618257458385,31520661477937912115,1750572856110551805720
%N A126147 a(n) = floor((Product_{k=1..n-1} prime(k))/prime(n)).
%C A126147 Every distinct prime dividing ((Product_{k=1..n-1} prime(k)) (mod prime(n))) also divides a(n).
%C A126147 Let Pn(n) = A002110(n) denote the primorial function. The number of natural numbers < Pn(n) that have prime(n+1) as a prime factor is equal to a(n). For example 19 numbers < Pn(4) = 210 have 11 as a prime factor. - _Jamie Morken_, Sep 18 2018
%H A126147 Muniru A Asiru, <a href="/A126147/b126147.txt">Table of n, a(n) for n = 1..185</a>
%p A126147 seq(floor(mul(ithprime(k),k=1..n-1)/ithprime(n)),n=1..20); # _Muniru A Asiru_, Sep 21 2018
%t A126147 f[n_] := Floor[ Product[ Prime@k, {k, n - 1}] / Prime@n]; Array[f, 19] (* _Robert G. Wilson v_, Mar 07 2007 *)
%Y A126147 Cf. A062347, A002110.
%K A126147 nonn
%O A126147 1,4
%A A126147 _Leroy Quet_, Mar 07 2007
%E A126147 More terms from _Robert G. Wilson v_, Mar 07 2007