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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

Table of n, a(n) for n=1..9.

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 October 15 15:29 EDT 2018. Contains 316236 sequences. (Running on oeis4.)