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A133194
Numbers requiring a prime number of chisel strokes for their representation in Roman numerals.
1
2, 3, 4, 5, 6, 8, 9, 10, 11, 13, 14, 16, 18, 19, 21, 23, 24, 26, 29, 31, 38, 41, 43, 44, 46, 49, 50, 51, 53, 54, 56, 58, 59, 61, 63, 64, 66, 69, 71, 78, 83, 84, 86, 88, 89, 91, 93, 94, 96, 99, 100, 101, 103, 104, 106, 108, 109, 111, 113, 114, 116, 119, 121
OFFSET
1,1
COMMENTS
Finite if one excludes multiple strokes chiseled over the letter, each meaning multiplication by 1000. The subsequence "primes requiring a prime number of chisel strokes for its representation in Roman numerals" begins 2, 3, 5, 11, 13, 19, 23, 29, 31, 41, 43, 53, 59, 61, 71, 83, 89, 101, 103. This sequence uses the definition of strokes given in A002963, not A118098.
LINKS
Nathaniel Johnston, Table of n, a(n) for n = 1..1215 (complete up to 3999)
FORMULA
A002963(a(n)) is in A000040.
EXAMPLE
a(1) = 2 because II requires 2 strokes (neglecting serifs).
a(44) = 88 because LXXXVIII requires 13 strokes.
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Oct 09 2007
STATUS
approved