cp's OEIS Frontend

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.

A131480 Minimal set of prime-strings in Roman numerals.

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%I A131480 #1 Nov 10 2007 03:00:00
%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.
%K A131480 base,nonn
%O A131480 1,1
%A A131480 Robert Happelberg (roberthappelberg(AT)yahoo.com), Jul 27 2007