OFFSET
0,3
LINKS
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 882
Index entries for linear recurrences with constant coefficients, signature (2,4,-4).
FORMULA
G.f.: -(-1+x)/(1-2*x-4*x^2+4*x^3)
Recurrence: {a(1)=1, a(0)=1, a(2)=6, 4*a(n)-4*a(n+1)-2*a(n+2)+a(n+3)=0}
Sum(-1/37*(-4-14*_alpha+13*_alpha^2)*_alpha^(-1-n), _alpha=RootOf(1-2*_Z-4*_Z^2+4*_Z^3))
MAPLE
spec := [S, {S=Sequence(Prod(Z, Union(Sequence(Z), Z, Z, Z, Z)))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
MATHEMATICA
CoefficientList[Series[(1-x)/(1-2x-4x^2+4x^3), {x, 0, 30}], x] (* or *) LinearRecurrence[{2, 4, -4}, {1, 1, 6}, 30] (* Harvey P. Dale, Jan 17 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
EXTENSIONS
More terms from James A. Sellers, Jun 08 2000
STATUS
approved