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 A231075 #9 Nov 05 2013 06:28:45 %S A231075 2,3,7,23,37,79,83,97,101,131,149,181,191,269,281,307,337,379,383,397, %T A231075 419,461,541,577,601,617,631,659,691,727,733,787,797,823,827,883,887, %U A231075 911,919,941,977,1013,1019,1051,1061,1129,1151,1153,1163,1171 %N A231075 Primes with a prime number of letters (A005589) in their (American) English name. %C A231075 Spaces and hyphens don't count, as in A005589. See A163648 and A231073 for the analogs counting syllables resp. words. %C A231075 Sequence A072686 is the British English analog, which in particular uses the additional "and": It features "one hundred and nine", but not "one hundred and one". In the present sequence, we do have "one hundred one" but not "one hundred nine". %H A231075 <a href="/index/Lc#letters">Index entries for sequences related to number of letters in n</a> %o A231075 (PARI) is(p)=isprime(A005589(p))&&isprime(p) %o A231075 (PARI) forprime(p=1,1200,isprime(A005589(p))&&print1(p",")) %K A231075 nonn,word %O A231075 1,1 %A A231075 _M. F. Hasler_, Nov 03 2013