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 A006968 Number of letters in Roman numeral representation of n. (Formerly M0417) 44
 1, 2, 3, 2, 1, 2, 3, 4, 2, 1, 2, 3, 4, 3, 2, 3, 4, 5, 3, 2, 3, 4, 5, 4, 3, 4, 5, 6, 4, 3, 4, 5, 6, 5, 4, 5, 6, 7, 5, 2, 3, 4, 5, 4, 3, 4, 5, 6, 4, 1, 2, 3, 4, 3, 2, 3, 4, 5, 3, 2, 3, 4, 5, 4, 3, 4, 5, 6, 4, 3, 4, 5, 6, 5, 4, 5, 6, 7, 5, 4, 5, 6, 7, 6, 5, 6, 7, 8, 6, 2, 3, 4, 5, 4, 3, 4, 5, 6, 4, 1, 2, 3, 4, 3, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS How is this sequence defined for large values? - Charles R Greathouse IV, Feb 01 2011 See A078715 for a discussion on the Roman 4M-problem. - Reinhard Zumkeller, Apr 14 2013 The sequence can be considered to be defined via the formula (as A055642 o A061493), so the question is to be posed in A061493, not here. - M. F. Hasler, Jan 12 2015 REFERENCES Netnews group rec.puzzles, Frequently Asked Questions (FAQ) file. (Science Section). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Nathaniel Johnston, Table of n, a(n) for n = 1..3999 Rec.puzzles, Archive Gerard Schildberger, The first 3999 numbers in Roman numerals Eric Weisstein's World of Mathematics, Roman Numerals Wikipedia, Roman numerals FORMULA A006968 = A055642 o A061493, i.e., a(n) = A055642(A061493(n)). - M. F. Hasler, Jan 11 2015 MAPLE A006968 := proc(n) return length(convert(n, roman)): end: seq(A006968(n), n=1..105); # Nathaniel Johnston, May 18 2011 MATHEMATICA a[n_] := StringLength[ IntegerString[ n, "Roman"]]; Table[a[n], {n, 1, 105}] (* Jean-François Alcover, Dec 27 2011 *) PROG (R) as.roman(1 :1024) # N. J. A. Sloane, Aug 23 2009 (Haskell) a006968 = lenRom 3 where    lenRom 0 z = z    lenRom p z = [0, 1, 2, 3, 2, 1, 2, 3, 4, 2] !! m + lenRom (p - 1) z'                 where (z', m) = divMod z 10 -- Reinhard Zumkeller, Apr 14 2013 (PARI) A006968(n)=#Str(A061493(n)) \\ M. F. Hasler, Jan 11 2015 CROSSREFS Cf. A002963, A036746, A036786, A036787, A036788, A061493, A092196, A160676, A160677, A199921. Sequence in context: A098236 A152978 A118121 * A058207 A105969 A275892 Adjacent sequences:  A006965 A006966 A006967 * A006969 A006970 A006971 KEYWORD nonn,base,nice,easy AUTHOR EXTENSIONS More terms from Eric W. Weisstein STATUS approved

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Last modified October 21 16:24 EDT 2019. Contains 328302 sequences. (Running on oeis4.)