OFFSET
0,3
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1,2).
FORMULA
a(n) = A014551(n), n>0.
a(n) = a(n-1) + 2*a(n-2), n>2.
G.f.: x*(1 + 4*x)/((1+x) * (1-2*x)).
a(n) = (-1)^n + 2^n for n>0. - Colin Barker, Jun 06 2012
E.g.f.: exp(2*x) + exp(-x) - 2. - G. C. Greubel, May 30 2016
MATHEMATICA
Join[{0, 1}, LinearRecurrence[{1, 2}, {5, 7}, 50]] (* or *) Table[2^n + (-1)^n, {n, 1, 25}] (* G. C. Greubel, May 30 2016 *)
CROSSREFS
KEYWORD
nonn,less,easy
AUTHOR
Paul Curtz, Oct 26 2009
EXTENSIONS
Edited and extended by R. J. Mathar, Mar 14 2010
STATUS
approved