A093704 - OEIS

%I #14 Aug 10 2020 09:49:51

%S 1,1,1,1,5,5,5,5,1,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,

%T 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,

%U 50,50,50,50,50,50,50,50,50,50,50,50,50,50,50,50,50,50,50

%N Value of initial digit of n in Roman numeral representation.

%H Nathaniel Johnston, <a href="/A093704/b093704.txt">Table of n, a(n) for n = 1..3999</a>

%H Stephanus Gibbs, <a href="http://www.softhawkway.com/rcalc.htm">Roman Numeral and Date Conversion</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RomanNumerals.html">Roman Numerals</a>

%e n=42 == XLII -> X == a(42)=10.

%p A093704 := proc(n) return convert(convert(n,roman)[1],arabic): end: seq(A093704(n),n=1..100); # _Nathaniel Johnston_, May 18 2011

%t FromDigits[StringTake[IntegerString[Range[70],"Roman"],1],"Roman"] (* _Harvey P. Dale_, Oct 10 2012 *)

%Y Cf. A000030.

%K nonn,easy,base

%O 1,5

%A _Reinhard Zumkeller_, May 17 2004