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 A216824 #13 Jan 26 2014 12:24:30 %S A216824 5,13,41,59,47057,4447,775807,713863,29133437,3892535183,110725121051, %T A216824 1456230512169437 %N A216824 Largest prime factor of the n-th Giuga number A007850(n). %C A216824 See A007850 for comments, references, and links. %e A216824 A007850(1) = 30 = 2*3*5 is the first Giuga number, so a(1) = 5. %Y A216824 Cf. A007850, A216823, A236434. %K A216824 nonn,hard,more %O A216824 1,1 %A A216824 _Jonathan Sondow_, Sep 17 2012