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 A045981 #10 Feb 16 2025 08:32:38 %S A045981 1,11,1121,1121211211,112121121121121112211221, %T A045981 112121121121121112211221211211122112211221123122212211 %N A045981 Describe all the previous terms!. %C A045981 Previous terms are described one by one in succession. Next terms are 118, 256, 564 and 1262 digits long. %H A045981 Reinhard Zumkeller, <a href="/A045981/b045981.txt">Table of n, a(n) for n = 1..9</a> %H A045981 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LookandSaySequence.html">Look and Say Sequence</a> %H A045981 Wikipedia, <a href="http://en.wikipedia.org/wiki/Look-and-say_sequence">Look-and-say sequence</a> %o A045981 (Haskell) %o A045981 a045981 n = a045981_list !! (n-1) %o A045981 a045981_list = 1 : f 1 [] where %o A045981 f x zs = y : f y zs' where %o A045981 y = read (concatMap show zs') %o A045981 zs' = zs ++ [a045918 x] %o A045981 -- _Reinhard Zumkeller_, Feb 28 2014 %Y A045981 Cf. A005150, A045982. %Y A045981 Cf. A045918. %K A045981 nonn,easy,base,nice %O A045981 1,2 %A A045981 _Anthony Joseph Splendora_ %E A045981 More terms from _Patrick De Geest_, Jun 15 1999