OFFSET
0,1
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..1000
José L. Ramírez, Gustavo N. Rubiano, and Rodrigo de Castro, A Generalization of the Fibonacci Word Fractal and the Fibonacci Snowflake, arXiv preprint arXiv:1212.1368 [cs.DM], 2012-2014.
Index entries for linear recurrences with constant coefficients, signature (2,1).
FORMULA
G.f.: -(10*x-3) / (x^2+2*x-1). - Colin Barker, Jul 10 2015
MATHEMATICA
LinearRecurrence[{2, 1}, {-3, 4}, 50] (* Harvey P. Dale, Apr 09 2022 *)
PROG
(Haskell)
a221173 n = a221173_list !! n
a221173_list = -3 : 4 : zipWith (+)
(map (* 2) $ tail a221173_list) a221173_list
-- Reinhard Zumkeller, Jan 04 2013
(PARI) Vec(-(10*x-3)/(x^2+2*x-1) + O(x^100)) \\ Colin Barker, Jul 10 2015
CROSSREFS
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Jan 04 2013
STATUS
approved