A195602 Primes written with prime number of Roman numerals.

2, 3, 7, 11, 19, 23, 41, 43, 47, 59, 61, 67, 79, 83, 97, 101, 109, 113, 131, 137, 149, 151, 157, 173, 199, 223, 227, 239, 241, 263, 281, 293, 311, 313, 317, 331, 349, 353, 401, 419, 421, 439, 443, 461, 463, 467, 479, 491, 509, 557, 569, 571, 577, 599, 601, 607, 619, 641, 643, 647

Offset: 1

Author

Juri-Stepan Gerasimov, Sep 21 2011

Keywords

• nonn
• base

Crossrefs

Cf. A003587, A195526.

Programs

Mathematica

Select[Prime[Range[200]],PrimeQ[Length[Characters[IntegerString[#, "Roman"]]]]&] (* Harvey P. Dale, Mar 19 2013 *)

PARI

Roman(n)=my(s);while(n,s+=[0,1,2,3,2,1,2,3,4,2][n%10+1];n\=10);s
forprime(p=2,3999,if(isprime(Roman(p)),print1(p", "))) \\ Charles R Greathouse IV, Oct 06 2011