A008603 Multiples of 21.

0, 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357, 378, 399, 420, 441, 462, 483, 504, 525, 546, 567, 588, 609, 630, 651, 672, 693, 714, 735, 756, 777, 798, 819, 840, 861, 882, 903, 924, 945, 966, 987

Offset

0,2

Comments

Sum of the numbers from 3*(n-1) to 3*(n+1). - Bruno Berselli, Oct 25 2018

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Tanya Khovanova, Recursive Sequences

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 333

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

Formula

G.f.: 21*x/(x-1)^2. - Vincenzo Librandi, Jun 10 2013

Mathematica

Range[0, 1500, 21] (* Vladimir Joseph Stephan Orlovsky, Jun 01 2011 *)
CoefficientList[Series[21 x / (x - 1)^2, {x, 0, 60}], x] (* Vincenzo Librandi, Jun 10 2013 *)

Prog

(PARI) a(n)=21*n \\ Charles R Greathouse IV, Oct 07 2015

Crossrefs

Cf. A008601, A008602.

Sequence in context: A037978 A089059 A114384 * A235497 A086794 A001682

Adjacent sequences: A008600 A008601 A008602 * A008604 A008605 A008606

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved