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 A057269 #2 May 20 2014 14:52:31 %S A057269 1,3,9,531441 %N A057269 a(n-1)+k=a(n) => a(n)^k=a(n+1). %C A057269 For +k and *k see A057268. %Y A057269 Cf. A057268. %K A057269 easy,nonn %O A057269 0,2 %A A057269 _Jonas Wallgren_, Aug 22 2000