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 A195602 #12 May 13 2013 01:49:56 %S A195602 2,3,7,11,19,23,41,43,47,59,61,67,79,83,97,101,109,113,131,137,149, %T A195602 151,157,173,199,223,227,239,241,263,281,293,311,313,317,331,349,353, %U A195602 401,419,421,439,443,461,463,467,479,491,509,557,569,571,577,599,601,607,619,641,643,647 %N A195602 Primes written with prime number of Roman numerals. %t A195602 Select[Prime[Range[200]],PrimeQ[Length[Characters[IntegerString[#, "Roman"]]]]&] (* _Harvey P. Dale_, Mar 19 2013 *) %o A195602 (PARI) Roman(n)=my(s);while(n,s+=[0,1,2,3,2,1,2,3,4,2][n%10+1];n\=10);s %o A195602 forprime(p=2,3999,if(isprime(Roman(p)),print1(p", "))) \\ _Charles R Greathouse IV_, Oct 06 2011 %Y A195602 Cf. A003587, A195526. %K A195602 nonn,base %O A195602 1,1 %A A195602 _Juri-Stepan Gerasimov_, Sep 21 2011