A036787 Length of Roman notation for n = length of decimal representation.

1, 5, 11, 15, 20, 40, 51, 55, 60, 90, 102, 104, 106, 109, 111, 115, 120, 140, 151, 155, 160, 190, 201, 205, 210, 250, 300, 401, 405, 410, 450, 502, 504, 506, 509, 511, 515, 520, 540, 551, 555, 560, 590, 601, 605, 610, 650, 700, 901, 905, 910, 950, 1003, 1007

Offset

1,2

Links

Nathaniel Johnston, Table of n, a(n) for n = 1..144 (complete up to 3999)

Formula

A006968(a(n)) = A055642(a(n)). - Reinhard Zumkeller, Apr 20 2013

Example

15 = XV has length 2 in both notations.

Maple

for n from 1 to 3999 do if(length(convert(n, roman)) = length(n))then printf("%d, ", n): fi: od: # Nathaniel Johnston, May 18 2011

Mathematica

Select[Range[1100], StringLength[IntegerString[#, "Roman"]] == IntegerLength[ #]&] (* Harvey P. Dale, Jul 25 2011 *)

Prog

(Haskell)
a036787 n = a036787_list !! (n-1)
a036787_list = [x | x <- [1..], a006968 x == a055642 x]
-- Reinhard Zumkeller, Apr 20 2013
(PARI) is_A036787(n)=#Str(n)==#Str(A061493(n)) \\ M. F. Hasler, Jan 12 2015

Crossrefs

Cf. A036786, A036788.

Sequence in context: A314036 A314037 A224213 * A182664 A299976 A187715

Adjacent sequences: A036784 A036785 A036786 * A036788 A036789 A036790

Keyword

nonn,base,easy,nice

Author

N. J. A. Sloane

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Sep 25 2000

Status

approved