OFFSET
0,1
COMMENTS
a(n) is the deficiency of 3^n * 5. - Patrick J. McNab, May 27 2017
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-3).
FORMULA
a(n) = 3*(a(n-1) - 2), a(0)=4.
From R. J. Mathar, Jan 05 2011: (Start)
G.f.: ( 4-10*x ) / ( (1-3*x)*(1-x) ).
a(n) = 2*A115098(n). (End)
a(n) = 4*a(n-1) - 3*a(n-2) for n>1. - Vincenzo Librandi, May 13 2014
MATHEMATICA
Table[3^n+3, {n, 0, 40}] (* or *) CoefficientList[Series[(4-10x)/((1-x) (1-3x)), {x, 0, 30}], x] (* Vincenzo Librandi, May 13 2014 *)
PROG
(Magma)[3^n+3: n in [0..35]];
(PARI) a(n)=3^n+3 \\ Charles R Greathouse IV, Oct 07 2015
(Sage) [3^n+3 for n in range(40)] # G. C. Greubel, Jan 27 2019
(GAP) List([0..40], n -> 3^n+3); # G. C. Greubel, Jan 27 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 25 2010
STATUS
approved