OFFSET
0,1
COMMENTS
Numbers whose digital root is 2. - Cino Hilliard, Dec 26 2006
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..5000
Tanya Khovanova, Recursive Sequences.
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
G.f.: (2 + 7*x)/(x - 1)^2. - R. J. Mathar, Jul 14 2016
E.g.f.: exp(x)*(2 + 9*x). - Stefano Spezia, Dec 07 2024
From Elmo R. Oliveira, Apr 12 2025: (Start)
a(n) = 2*a(n-1) - a(n-2).
a(n) = A016789(3*n). (End)
MATHEMATICA
Range[2, 1000, 9] (* Vladimir Joseph Stephan Orlovsky, May 28 2011 *)
LinearRecurrence[{2, -1}, {2, 11}, 60] (* Harvey P. Dale, Jun 09 2023 *)
PROG
(Magma) [9*n+2: n in [0..60]]; // Vincenzo Librandi, Jul 23 2011
(PARI) a(n)=9*n+2 \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Cino Hilliard, Dec 26 2006
STATUS
approved
