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 A050933 #6 Nov 09 2018 14:23:43 %S A050933 0,1,2,3,4,5,6,8,11,20,100,1000,1000000,1000000000,1000000000000000, %T A050933 1000000000000000000000000,1000000000000000000000000000 %N A050933 Numbers k with property that spelling k in American English requires a new letter of the alphabet. %C A050933 The large numbers are (new letter in uppercase): "one Billion" (10^9), "one Quadrillon" (10^15), "one sePtillion" (10^24) and "one oCtillion" (10^27). Their names and definitions are based on the American system. %H A050933 Landon Curt Noll, <a href="http://www.isthe.com/cgi-bin/number.cgi">The English name of a number</a> %H A050933 R. Rowlett, <a href="http://www.unc.edu/~rowlett/units/large.html">Names for large numbers</a> %e A050933 Spelling "zero" requires letters "z", "e", "r", "o". Spelling "one" requires a new letter, "n". Spelling "two" requires new letters, "t" and "w"; etc. Letters "j" and "k" are never used. %e A050933 "1000" (one thousand) is the smallest number that requires an "a". %K A050933 easy,fini,full,nonn,word %O A050933 0,3 %A A050933 Jean Fontaine (jfontain(AT)odyssee.net), Dec 30 1999 %E A050933 Corrected by _Andrew Weimholt_, Sep 27 2009