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 A259921 #28 Dec 02 2015 12:07:01 %S A259921 1,3,5,15,30,40,50,103,105,115,130,140,150,204,214,240,250,316,317,325 %N A259921 a(n) is the smallest positive integer > a(n-1) with exactly n letters when written in Spanish. %C A259921 a(6) = 15 = "quince" (6 letters); 4 = "cuatro" also has 6 letters but is smaller than 5 = a(5) and this sequence is strictly increasing. %C A259921 Spaces are not counted, so, e.g., "ciento tres" and "doscientos cuatro" are treated as a 10-letter word and a 16-letter word, respectively. %H A259921 Wikipedia, <a href="https://es.wikipedia.org/wiki/Anexo:Nombres_de_los_n%C3%BAmeros_en_espa%C3%B1ol">Anexo:Nombres de los números en español</a> %e A259921 a( 3) = 1 for the 3-letter word "uno"; %e A259921 a( 4) = 3 for the 4-letter word "tres"; %e A259921 a( 5) = 5 for the 5-letter word "cinco"; %e A259921 a( 6) = 15 for the 6-letter word "quince"; %e A259921 a( 7) = 30 for the 7-letter word "treinta"; %e A259921 a( 8) = 40 for the 8-letter word "cuarenta"; %e A259921 a( 9) = 50 for the 9-letter word "cincuenta"; %e A259921 a(10) = 103 for the 10-letter word "cientotres"; %e A259921 ... %e A259921 a(16) = 204 for the 16-letter word "doscientoscuatro"; %e A259921 .... %Y A259921 Cf. A084390 (this sequence for English), A161353 (this sequence without the increasing condition). %K A259921 nonn,word,less %O A259921 3,2 %A A259921 _Rodolfo Kurchan_, Jul 08 2015