OFFSET
0,1
COMMENTS
Old name was "a(2n), where a(n) is A073145".
LINKS
FORMULA
G.f.: (3 + 2*x + 3*x^2)/(1 + x + 3*x^2 - x^3).
a(2n)=-a(2n-2)-3a(2n-4)+a(2n-6), a(0)=3, a(2)=-1, a(4)=-5.
Recurrence: a(n) = a(n-3) - 3a(n-2) - a(n-1), starting 3,-1,-5.
MATHEMATICA
CoefficientList[Series[(3 + 2*x + 3*x^2)/(1 + x + 3*x^2 - x^3), {x, 0, 50}], x]
LinearRecurrence[{-1, -3, 1}, {3, -1, -5}, 40] (* Harvey P. Dale, Aug 22 2018 *)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Aug 03 2002
STATUS
approved