OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (4,-4,1).
FORMULA
a(n) = 3*a(n-1) - a(n-2) + 1.
a(n) = 4*a(n-1) - 4*a(n-2) + a(n-3).
a(n) = 3*a(n-1) - 3*a(n-3) + a(n-4).
a(n) = 9*A001519(n+1) - 1.
G.f.: (8 - 15*x + 8*x^2)/((1-x)*(1-3*x+x^2)). - Jaume Oliver Lafont, Aug 30 2009
MATHEMATICA
LinearRecurrence[{4, -4, 1}, {8, 17, 44}, 25] (* G. C. Greubel, Aug 31 2016 *)
PROG
(Magma) [9*Fibonacci(2*n+1)-1: n in [0..30]]; // Vincenzo Librandi, Aug 07 2011
(PARI) a(n)=9*fibonacci(2*n+1)-1 \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Jan 03 2009
STATUS
approved