The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A160677 Numbers k such that k, 2k and 3k use the same number of characters when expressed in Roman numerals. 4

%I

%S 2,7,20,22,36,70,72,97,153,200,202,207,220,222,236,315,351,360,362,

%T 379,448,653,700,702,707,720,722,736,871,970,972,997,1035,1087,1177,

%U 1235,1267,1350,1352,1357,1386,1537,1677,1735,1767,1818,1836,1870,1872,1897

%N Numbers k such that k, 2k and 3k use the same number of characters when expressed in Roman numerals.

%C 2 = II, 4 = IV, 6 = VI;

%C 7 = VII, 14 = XIV, 21 = XXI;

%C 20 = XX, 40 = XL, 60 = LX.

%H Nathaniel Johnston, <a href="/A160677/b160677.txt">Table of n, a(n) for n = 1..57</a> (complete up to 3999)

%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)))then printf("%d, ", n): fi: od: # _Nathaniel Johnston_, May 18 2011

%Y Cf. A006968.

%K nonn,easy

%O 1,1

%A _Claudio Meller_, May 23 2009, May 24 2009

%E Extended by _Nathaniel Johnston_, May 18 2011

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 2 02:12 EST 2021. Contains 349435 sequences. (Running on oeis4.)