OFFSET
0,1
COMMENTS
a(n) = (1 + (-1)^n)*L(n) + ((-1)^n)*L(n-1), L(n) Lucas numbers.
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,3,0,-1).
FORMULA
a(n) = 3*a(n-2) - a(n-4); a(0)=3, a(1)=-2, a(2)=7, a(3)=-3.
O.g.f. (3-2*x-2*x^2+3*x^3)/(1-3*x^2+x^4).
MATHEMATICA
CoefficientList[Series[(3-2x-2x^2+3x^3)/(1-3x^2+x^4), {x, 0, 40}], x]
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Sep 12 2002
STATUS
approved