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 A081261 #3 Mar 30 2012 17:27:18 %S A081261 4,6,6,5,5,6,6,6,6,5,5,6,6,6,6,5,5,6,6,6,5,5,6,6,6,5,5,6,6,6,6,5,5,6, %T A081261 6,6,6,5,5,6,6,6,6,5,5,6,6,6,6,5,5,6,6,6,5,5,6,6,6,5,5,6,6,6,6,5,5,6, %U A081261 6,6,6,5,5,6,6,6,6,5,5,6,6,6,6,5,5,6,6,6,5,5,6,6,6,5,5,6,6,6,6,5,5,6,6,6,6 %N A081261 Start with a(1)=4; apply 4 -> 665, 5 -> 56665, 6 -> 566665; iterate. %C A081261 a(n)= A081260(n) - A081260(n-1) (taking A081260(0) as equal to 0). Sum of first n terms = A081260(n). %e A081261 4 -> 665 -> 56666556666556665 -> ... %Y A081261 Cf. A079000, A079948. %K A081261 easy,nonn %O A081261 1,1 %A A081261 _Matthew Vandermast_, Mar 14 2003