|
|
A120433
|
|
Numbers n with property that Roman numeral for n uses the subtractive notation.
|
|
1
|
|
|
4, 9, 14, 19, 24, 29, 34, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 54, 59, 64, 69, 74, 79, 84, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 104, 109, 114, 119, 124, 129, 134, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 154, 159, 164, 169, 174
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
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
|
|
LINKS
|
|
|
EXAMPLE
|
In Roman numerals, 14 is XIV, that is, X + (V - I) = 10 + (5 - 1) = 14, so 14 is in the sequence.
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.
|
|
MAPLE
|
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
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,easy,nonn
|
|
AUTHOR
|
Christian Amet (chr.amet(AT)infonie.fr), Jul 13 2006
|
|
STATUS
|
approved
|
|
|
|