OFFSET
0,3
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Hirschhorn, Michael D., Non-trivial intertwined second-order recurrence relations, Fibonacci Quart. 43 (2005), no. 4, 316-325. See p. 324.
Index entries for linear recurrences with constant coefficients, signature (-1,-5,1,-1).
FORMULA
From Colin Barker, Dec 27 2017: (Start)
G.f.: (1 + 2*x + 2*x^2) / (1 + x + 5*x^2 - x^3 + x^4).
a(n) = -a(n-1) - 5*a(n-2) + a(n-3) - a(n-4) for n>3.
(End)
MATHEMATICA
CoefficientList[ Series[(1 +2x +2x^2)/(1 +x +5x^2 -x^3 +x^4), {x, 0, 33}], x] (* or *)
LinearRecurrence[{-1, -5, 1, -1}, {1, 1, -4, 0}, 33] (* Robert G. Wilson v, Dec 27 2017 *)
PROG
(PARI) Vec((1 + 2*x + 2*x^2) / (1 + x + 5*x^2 - x^3 + x^4) + O(x^40)) \\ Colin Barker, Dec 27 2017
CROSSREFS
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Nov 12 2011
STATUS
approved