OFFSET
0,2
LINKS
Georg Fischer, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-3,4).
FORMULA
a(n) = 4*a(n-2) - 3*a(n-1), a(0)= 1, a(1)= 2, for n>1.
a(n) = 6 - 4*a(n-1), a(0)=1.
a(n) = a(n-1) + (-4)^(n-1), a(0)=1.
G.f.: (1+5x)/(1+3x-4x^2).
E.g.f.: (6*exp(x) - exp(-4x))/5.
MATHEMATICA
Table[(6 - (-4)^n)/5, {n, 0, 100}] (* G. C. Greubel, Apr 24 2016 *)
PROG
(PARI) a(n)=(6-(-4)^n)/5 \\ Charles R Greathouse IV, Apr 28 2016
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Philippe Deléham, Oct 06 2009
EXTENSIONS
a(12) onward changed by Georg Fischer, May 03 2019
STATUS
approved