OFFSET
0,3
COMMENTS
Limiting ratio is 1.61791..., the real root of -1 + x^2 - x^18 - x^19 + x^20. Signature in Mathematica is:
-CoefficientList[1 - x - x^2 + x^18 - x^20, x]
{-1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 1}.
The sequence agrees with the Fibonacci numbers (A000045) for the first 18 terms.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
David Terr and Eric W. Weisstein, MathWorld: Pisot Number
Index entries for linear recurrences with constant coefficients, signature (1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 1).
MATHEMATICA
CoefficientList[Series[1/(1 - x - x^2 + x^18 - x^20), {x, 0, 50}], x]
PROG
(PARI) Vec(1/(1-x-x^2+x^18-x^20) + O(x^50)) \\ G. C. Greubel, Nov 16 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Roger L. Bagula, Jan 21 2012
STATUS
approved