OFFSET
0,2
COMMENTS
lim_{n -> infinity} a(n)/a(n-1) = 16.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (20, -64).
FORMULA
a(n) = (7*16^n - 4^n)/6.
G.f.: (1 - 2*x)/((1-4*x)*(1-16*x)).
E.g.f.: (1/6)*(7*exp(16*x) - exp(4*x)). - G. C. Greubel, May 28 2016
MATHEMATICA
LinearRecurrence[{20, -64}, {1, 18}, 50] (* G. C. Greubel, May 28 2016 *)
PROG
(Magma) [ n le 2 select 17*n-16 else 20*Self(n-1)-64*Self(n-2): n in [1..17] ];
CROSSREFS
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Oct 23 2009
STATUS
approved