%I #24 Jan 09 2020 12:06:27
%S 36,153,315,351,360,448,736,1386
%N Numbers k such that k, 2k, 3k and 4k use the same number of characters when expressed in Roman numerals.
%C This sequence is complete up to 3999.
%e 1*36 = 36 = XXXVI,
%e 2*36 = 72 = LXXII,
%e 3*36 = 108 = CVIII,
%e 4*36 = 144 = CXLIV,
%e so 36 is a term;
%e 1*153 = 153 = CLIII,
%e 2*153 = 306 = CCCVI,
%e 3*153 = 459 = CDLIX,
%e 4*153 = 612 = DCXII,
%e so 153 is a term.
%p 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
%Y See A006968 for the basic underlying sequence.
%K nonn,easy
%O 1,1
%A _Claudio Meller_, May 25 2009
%E a(8) from _Nathaniel Johnston_, May 18 2011
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