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 A262225 #18 Oct 02 2015 12:24:18
%S A262225 5,3,2,31,19,431,3457,24907963,250198320553451,
%T A262225 164072502171958410481596412086571,
%U A262225 15268641997545743809809010755124846521575738536063
%N A262225 Euclid-Mullin sequence: a(1) = 5, a(n+1) is largest prime factor of Product_{k=1..n} a(k) + 1.
%C A262225 This is similar to A000946 but starting a(1) = 5.
%H A262225 Ben Meekins, <a href="/A262225/b262225.txt">Table of n, a(n) for n = 1..12</a>
%t A262225 a = {5}; Do[AppendTo[a, FactorInteger[Product[a[[k]], {k, n - 1}] + 1][[-1, 1]]], {n, 2, 11}]; a (* _Michael De Vlieger_, Sep 15 2015 *)
%Y A262225 Cf. A000946.
%K A262225 nonn
%O A262225 1,1
%A A262225 _Ben Meekins_, Sep 15 2015