A008600 Multiples of 18.

0, 18, 36, 54, 72, 90, 108, 126, 144, 162, 180, 198, 216, 234, 252, 270, 288, 306, 324, 342, 360, 378, 396, 414, 432, 450, 468, 486, 504, 522, 540, 558, 576, 594, 612, 630, 648, 666, 684, 702, 720, 738, 756, 774, 792, 810, 828, 846, 864, 882, 900, 918, 936

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Tanya Khovanova, Recursive Sequences.
• INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 330.
• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Cf. A008591, A008598, A044102, A154612.

Programs

Mathematica

Range[0, 1000, 18] (* Vladimir Joseph Stephan Orlovsky, Jun 01 2011 *)
CoefficientList[Series[18 x / (x - 1)^2, {x, 0, 60}], x] (* Vincenzo Librandi, Jun 10 2013 *)
18*Range[0,60] (* Harvey P. Dale, Jan 15 2023 *)

PARI

a(n)=18*n \\ Charles R Greathouse IV, Sep 24 2015

Formula

G.f.: 18*x/(x-1)^2. - Vincenzo Librandi, Jun 10 2013

From Elmo R. Oliveira, Apr 10 2025: (Start)

E.g.f.: 18*x*exp(x).

a(n) = 18*n = 2*A008591(n) = A044102(n)/2.

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