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A160754
Numbers k such that k, 2k, 3k and 4k use the same number of characters when expressed in Roman numerals.
0
36, 153, 315, 351, 360, 448, 736, 1386
OFFSET
1,1
COMMENTS
This sequence is complete up to 3999.
EXAMPLE
1*36 = 36 = XXXVI,
2*36 = 72 = LXXII,
3*36 = 108 = CVIII,
4*36 = 144 = CXLIV,
so 36 is a term;
1*153 = 153 = CLIII,
2*153 = 306 = CCCVI,
3*153 = 459 = CDLIX,
4*153 = 612 = DCXII,
so 153 is a term.
MAPLE
for n from 1 to 3999 do if(length(convert(n, roman)) = length(convert(2*n, roman)) and length(convert(n, roman)) = length(convert(3*n, roman)) and length(convert(n, roman)) = length(convert(4*n, roman)))then printf("%d, ", n): fi: od: # Nathaniel Johnston, May 18 2011
CROSSREFS
See A006968 for the basic underlying sequence.
Sequence in context: A039495 A263120 A034592 * A275496 A117511 A250632
KEYWORD
nonn,easy
AUTHOR
Claudio Meller, May 25 2009
EXTENSIONS
a(8) from Nathaniel Johnston, May 18 2011
STATUS
approved