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 A072686 #6 Nov 05 2013 06:27:47 %S A072686 2,3,7,23,37,79,83,97,109,139,157,163,167,199,211,229,239,257,263,271, %T A072686 313,401,421,431,449,491,503,521,569,643,647,653,709,719,751,761,809, %U A072686 907,991,1021,1031,1049,1069,1091,1103,1301,1303,1307,1327,1409,1511 %N A072686 Prime numbers whose (British) English names have a prime number of letters. %C A072686 See A231075 for the American English version. The sequences coincide up to a(8)=97 but are then completely different, due to the additional "and" (e.g. in "one hundred and nine") in the British style. - _M. F. Hasler_, Nov 03 2013 %H A072686 <a href="/index/Lc#letters">Index entries for sequences related to number of letters in n</a> %e A072686 e.g. 2003 -> "TWOTHOUSANDANDTHREE" -> 19 letters and 19 is prime. Note that the "and" naming convention is used; e.g. "ONE HUNDRED AND ONE", "ONE THOUSAND NINE HUNDRED AND SEVENTY THREE". %Y A072686 Prime elements of A072685. %K A072686 easy,nonn,word %O A072686 0,1 %A A072686 Mark Hudson (mrmarkhudson(AT)hotmail.com), Jul 02 2002