OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (5, -4).
FORMULA
a(n) = -A156591(2n+1).
a(n) = 4*a(n-1) - 20, n > 0.
G.f.: (7 - 27*x)/((1-x)*(1-4*x)). - R. J. Mathar, Feb 23 2009
E.g.f.: (1/3)*(20*exp(x) + exp(4*x)). - G. C. Greubel, Jun 25 2021
MATHEMATICA
(4^Range[0, 40] + 20)/3 (* G. C. Greubel, Jun 25 2021 *)
PROG
(Magma) [(4^n+20)/3: n in [0..35]]; // Vincenzo Librandi, Jul 24 2011
(SageMath) [(4^n + 20)/3 for n in (0..40)] # G. C. Greubel, Jun 25 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Feb 11 2009
EXTENSIONS
Edited and extended by R. J. Mathar, Feb 23 2009
STATUS
approved