%I A131480
%S A131480 2,5,11,59,101,509,1009,1051,3001
%N A131480 Minimal set of prime-strings in Roman numerals.
%C A131480 Written in Roman numerals this sequence begins II, V, XI, LIX, CI, DIX, 
               MIX, MLI, MMMI.
%C A131480 For a while I actually considered putting in 97 (XCVII) instead of 101 
               (CI), since XCVII contains CI as a substring. But it also contains 
               II, V and XI as substrings, so going in order strictly from smallest 
               to greatest, 97 must be excluded.
%e A131480 a(4) = 59 because it is a prime number and in Roman numerals it's written 
               LIX (all the substrings are composite or not prime: L, LI, LX, I, 
               IX, X).
%Y A131480 Cf. A071062, minimal set of prime-strings in base 10.
%Y A131480 Sequence in context: A089609 A087185 A127010 this_sequence A018847 A134996 
               A134998
%Y A131480 Adjacent sequences: A131477 A131478 A131479 this_sequence A131481 A131482 
               A131483
%K A131480 base,nonn
%O A131480 1,1
%A A131480 Robert Happelberg (roberthappelberg(AT)yahoo.com), Jul 27 2007