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 A131480 Minimal set of prime-strings in Roman numerals. 1
 2, 5, 11, 59, 101, 509, 1009, 1051, 3001 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Written in Roman numerals this sequence begins II, V, XI, LIX, CI, DIX, MIX, MLI, MMMI. 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. LINKS EXAMPLE 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). CROSSREFS Cf. A071062, minimal set of prime-strings in base 10. Sequence in context: A087185 A127010 A140547 * A262228 A213073 A267527 Adjacent sequences:  A131477 A131478 A131479 * A131481 A131482 A131483 KEYWORD base,nonn AUTHOR Robert Happelberg (roberthappelberg(AT)yahoo.com), Jul 27 2007 STATUS approved

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Last modified May 9 10:16 EDT 2021. Contains 343731 sequences. (Running on oeis4.)