OFFSET
1,1
REFERENCES
Posting to sci.math.research by dima(AT)win.tue.nl (Dmitrii V. Pasechnik), Oct 28 1996.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
D. Pasechnik, Poincare series for the depths of roots in a root system, Sci. Math. Research posting Oct 28 1996.
Index entries for linear recurrences with constant coefficients, signature (2,2,-3).
FORMULA
a(n) = 2*a(n-1) + 2*a(n-2) - 3*a(n-3).
G.f.: -x*(4*x^2+x-2) / ((x-1)*(3*x^2+x-1)). - Colin Barker, Sep 27 2013
a(n) = (78 + (13-5*sqrt(13))*((1-sqrt(13))/2)^n + ((1+sqrt(13))/2)^n*(13+5*sqrt(13))) / 78. - Colin Barker, Aug 03 2017
MATHEMATICA
CoefficientList[Series[-(4 x^2 + x - 2)/((x - 1) (3 x^2 + x - 1)), {x, 0, 50}], x] (* Vincenzo Librandi, Sep 27 2013 *)
LinearRecurrence[{2, 2, -3}, {2, 3, 6}, 30] (* Harvey P. Dale, Nov 28 2014 *)
PROG
(PARI) Vec(-x*(4*x^2+x-2)/((x-1)*(3*x^2+x-1)) + O(x^100)) \\ Colin Barker, Sep 27 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved