OFFSET
0,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (-1,1,-1,1).
FORMULA
a(n) = (-1)^n*T(n), where T(n) are the generalized tetranacci numbers A073817.
a(n) = -a(n-1)+a(n-2)-a(n-3)+a(n-4), a(0)=4, a(1)=-1, a(2)=3, a(3)=-7.
G.f.: (4+3x-2x^2+x^3)/(1+x-x^2+x^3-x^4).
MATHEMATICA
CoefficientList[Series[4+3*x-2*x^2+x^3)/(1+x-x^2+x^3-x^4), {x, 0, 40}], x]
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Aug 19 2002
STATUS
approved