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 A230862 #15 Jul 09 2025 04:37:35 %S A230862 0,1,8,10,19,90 %N A230862 Start with 0; each term when spelled out must start with the last letter of the previous term and must be the smallest such number that is greater than the previous term. %C A230862 Two variations are possible: Not requiring monotonicity (i.e., the sequence could go: ZerO, OnE, EighT, TeN, NinE, EighteeN, NineteeN, ...), and imposing the additional constraint that the sequence does not stop right after the chosen number (so "NinetY" would be forbidden and "Ninety-onE" should be used instead). See A227865 for a French and A228442 for a German version using such rules. - _M. F. Hasler_, Nov 03 2013 %D A230862 David J. Bodycombe, "Riddles of the Sphinx", apparently mentions this puzzle. %H A230862 E. Angelini, <a href="https://web.archive.org/web/*/http://list.seqfan.eu/oldermail/seqfan/2013-November/011824.html">Re: A sequence in your style</a>, SeqFan list, Nov 01 2013 %H A230862 <a href="/index/En#English">Index entries for sequences related to the English words for numbers</a> %e A230862 ZerO, OnE, EighT, TeN, NineteeN, NinetY (ends) %Y A230862 Cf. A227865, A228442. %K A230862 nonn,fini,full,word %O A230862 0,3 %A A230862 _N. J. A. Sloane_, Oct 31 2013, based on an email from George I. Bell, Boulder, CO