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 A260188 #29 Aug 09 2022 14:17:57
%S A260188 1,2,2,2,2,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,30,30,30,
%T A260188 30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,
%U A260188 30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30
%N A260188 Greatest primorial less than or equal to n.
%H A260188 Charles R Greathouse IV, <a href="/A260188/b260188.txt">Table of n, a(n) for n = 1..10000</a>
%F A260188 a(n) = max_{A034386(i) <= n} A034386(i).
%F A260188 a(n) >> n/log n. - _Charles R Greathouse IV_, Jul 20 2015
%F A260188 Sum_{n>=1} 1/a(n)^2 = A249270. - _Amiram Eldar_, Aug 09 2022
%e A260188 a(5) = 2 because 2 is the greatest primorial less than or equal to 5.
%e A260188 a(31) = 30 because 30 is the greatest primorial less than or equal to 31.
%t A260188 Table[k = 0; While[Times @@ Prime@ Range[k + 1] <= n, k++]; Times @@ Prime@ Range@ k, {n, 120}] (* _Michael De Vlieger_, Aug 30 2016 *)
%o A260188 (PARI) a(n)=my(t=1,k); forprime(p=2,, k=t*p; if(k>n, return(t), t=k)) \\ _Charles R Greathouse IV_, Jul 20 2015
%Y A260188 Cf. A034386 (primorials), A048764, A249270.
%K A260188 nonn
%O A260188 1,2
%A A260188 _Jean-Marc Rebert_, Jul 18 2015