OFFSET
0,1
COMMENTS
a(n)=((-1)^n+1)L(n), L(n)=Lucas number.
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,3,0,-1).
FORMULA
a(n)=3a(n-2)-a(n-4), a(0)=4, a(1)=0, a(2)=6, a(3)=0. G.f.: (4-6x^2)/(1-3x^2+x^4).
MATHEMATICA
CoefficientList[Series[(4 - 6*x^2)/(1 - 3*x^2 + x^4), {x, 0, 50}], x]
LinearRecurrence[{0, 3, 0, -1}, {4, 0, 6, 0}, 50] (* or *) Riffle[ LinearRecurrence[ {3, -1}, {4, 6}, 30], 0] (* Harvey P. Dale, Aug 17 2018 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Aug 31 2002
STATUS
approved