OFFSET
0,2
COMMENTS
LINKS
Clark Kimberling, Table of n, a(n) for n = 0..2000
Index entries for linear recurrences with constant coefficients, signature (1, 3, -2, -2)
FORMULA
a(n) = a(n-1) + a(n-3) + a(n-4), where a(0) = -1, a(1) = -2, a(2) = 1, a(3) = 1.
G.f.: (-1 - x + 6 x^2 + 4 x^3)/(1 - x - 3 x^2 + 2 x^3 + 2 x^4).
MATHEMATICA
LinearRecurrence[{1, 3, -2, -2}, {-1, -2, 1, 1}, 37] (* corrected by Georg Fischer, Apr 03 2019 *)
PROG
(PARI) x='x+O('x^37); Vec((-1 - x + 6*x^2 + 4*x^3)/(1 - x - 3*x^2 + 2*x^3 + 2*x^4)) \\ Georg Fischer, Apr 03 2019
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Clark Kimberling, Feb 09 2018
EXTENSIONS
a(2)=1 corrected by Georg Fischer, Apr 03 2019
STATUS
approved