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 A083685 #18 Jan 15 2022 17:04:14
%S A083685 2,3,5,11,59,59,419,839,5039,5039,55439,55439,1081079,1081079,1081079,
%T A083685 1441439,24504479,24504479,232792559,232792559,232792559,232792559,
%U A083685 5354228879,5354228879,53542288799,53542288799,1044074631599
%N A083685 a(n) is the smallest prime of the form k*lcm(1..n) - 1.
%H A083685 Harvey P. Dale, <a href="/A083685/b083685.txt">Table of n, a(n) for n = 1..500</a>
%e A083685 a(9) = 5039: lcm(1..9) = 2520; 2519 is not a prime but 2*2520 - 1 = 5039 is a prime.
%t A083685 spf[n_]:=Module[{c=LCM@@Range[n],k=1},While[!PrimeQ[k*c-1],k++];k*c-1]; Array[spf,30] (* _Harvey P. Dale_, Jan 15 2022 *)
%o A083685 (PARI) a(n) = {my(lcmn = lcm(vector(n, k, k)), k = 1); while(!isprime(p = k*lcmn-1), k++); p;} \\ _Michel Marcus_, Mar 15 2018
%Y A083685 Cf. A070858.
%K A083685 nonn
%O A083685 1,1
%A A083685 _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 15 2003
%E A083685 Corrected and extended by _Vladeta Jovovic_, Jun 16 2003