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 A121064 #32 Apr 24 2023 12:55:53
%S A121064 0,0,0,4,4,6,6,3,13,22,35,32,36,89,158,342,586,913,1490,2365,3884,
%T A121064 5940,8629,12386,17637,26311
%N A121064 Number of length-n American English expressions for nonnegative integers (spaces, hyphens, and commas excluded).
%C A121064 These are Mathematica integer names (using qualifier "Words") < 10^306.
%D A121064 GCHQ, The GCHQ Puzzle Book, Penguin, 2016. See page 123, Problem 6.
%H A121064 Hans Havermann, <a href="https://gladhoboexpress.blogspot.com/2021/06/a-dictionary-of-american-english.html">A dictionary of American English integer names (by letter count, to 13 letters)</a>.
%H A121064 Hans Havermann, <a href="http://gladhoboexpress.blogspot.com/2021/06/14-to-40-letter-integer-names.html">14- to 40-letter integer names</a>.
%F A121064 a(n) = # {m | A005589(m)=n }. - _M. F. Hasler_, Sep 07 2012
%e A121064 a(3) = 4 since there are only 4 numbers in English with 3 letters: one, two, six, ten.
%e A121064 a(4) = 4 since there are only 4 numbers in English with 4 letters: zero, four, five, nine.
%e A121064 a(10) = 35 (24, 25, 29, 34, 35, 39, 43, 47, 48, 53, 57, 58, 63, 67, 68, 71, 72, 76, 84, 85, 89, 94, 95, 99, 100, 200, 600, 1000000, 2000000, 6000000, 10000000, 1000000000, 2000000000, 6000000000, 10000000000)
%e A121064 a(11) = 32: [2389][378],7[459], [459]00, [126]000, 10000, [459]000000, [459]000000000, [126]000000000000, 10 trillion.
%Y A121064 Cf. A052193, A362449.
%K A121064 more,nonn,word,fini
%O A121064 0,4
%A A121064 _Ray G. Opao_, Aug 10 2006
%E A121064 Corrected and extended by _Hans Havermann_, Sep 08 2012
%E A121064 Recorrected (using a larger number limit) by _Hans Havermann_, Apr 23 2023