A242181 Numbers with four X's in Roman numerals.

39, 89, 139, 189, 239, 289, 339, 389, 439, 489, 539, 589, 639, 689, 739, 789, 839, 889, 939, 989, 1039, 1089, 1139, 1189, 1239, 1289, 1339, 1389, 1439, 1489, 1539, 1589, 1639, 1689, 1739, 1789, 1839, 1889, 1939, 1989, 2039, 2089, 2139, 2189, 2239, 2289, 2339

Offset

1,1

Comments

All these end in XXXIX.

Links

Table of n, a(n) for n=1..47.

Eric Weisstein's World of Mathematics, Roman Numerals.

Wikipedia, Roman numerals.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

a(n) = 50*n - 11. - Charles R Greathouse IV, May 06 2014

From Elmo R. Oliveira, May 20 2026: (Start)

G.f.: x*(39 + 11*x)/(1 - x)^2.

E.g.f.: exp(x)*(50*x - 11) + 11.

a(n) = 2*A008607(n) - 11.

a(n) = 2*a(n-1) - a(n-2). (End)

Example

39 = XXXIX; 89 = LXXXIX.

Maple

A242181:=n->50*n-11; seq(A242181(n), n=1..50); # Wesley Ivan Hurt, May 07 2014
# Alternative: for the Roman version.
[seq(convert(50*n-11, roman), n=1..50)]; # Wolfdieter Lang, May 09 2014

Mathematica

Table[50 n - 11, {n, 50}] (* Wesley Ivan Hurt, May 07 2014 *)

Prog

(PARI) a(n)=50*n-11 \\ Charles R Greathouse IV, May 06 2014

Crossrefs

Cf. A006968, A008607.

Sequence in context: A020264 A044177 A044558 * A020168 A063318 A039422

Adjacent sequences: A242178 A242179 A242180 * A242182 A242183 A242184

Keyword

nonn,base,easy

Author

J. Lowell, May 06 2014

Extensions

More terms from Wesley Ivan Hurt, May 07 2014

Status

approved