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%I #13 Jan 21 2018 02:33:14
%S 4,9,14,19,24,29,34,39,40,41,42,43,44,45,46,47,48,49,54,59,64,69,74,
%T 79,84,89,90,91,92,93,94,95,96,97,98,99,104,109,114,119,124,129,134,
%U 139,140,141,142,143,144,145,146,147,148,149,154,159,164,169,174
%N Numbers n with property that Roman numeral for n uses the subtractive notation.
%C Each number in this sequence has a 4 or a 9 in its decimal representation, corresponding to one of IV, IX, XL, XC, CD, CM. - _Alonso del Arte_, Jan 05 2018
%H Nathaniel Johnston, <a href="/A120433/b120433.txt">Table of n, a(n) for n = 1..1952</a> (complete up to 3999)
%e In Roman numerals, 14 is XIV, that is, X + (V - I) = 10 + (5 - 1) = 14, so 14 is in the sequence.
%e In Roman numerals, 15 is XV, meaning X + V = 10 + 5 = 15, which does not use subtractive notation, so 15 is not in the sequence.
%p with(StringTools): for n from 1 to 300 do r:=convert(n,roman): if(Search("IV",r)>0 or Search("IX",r)>0 or Search("XL",r)>0 or Search("XC",r)>0 or Search("CD",r)>0 or Search("CM",r)>0)then printf("%d, ", n): fi: od: # _Nathaniel Johnston_, May 18 2011
%K base,easy,nonn
%O 1,1
%A Christian Amet (chr.amet(AT)infonie.fr), Jul 13 2006
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