OFFSET
0,2
COMMENTS
Hankel transform of A132310. [From Paul Barry, Apr 26 2009]
LINKS
FORMULA
G.f.: (1-2x)/(1+2x+4x^2).
a(n)=Product{k=0..n, (3*cos(2*pi*(k-1)/3)/2-5/4-2*0^k)^(n-k)};
a(n) = 2^n*A061347(n+2) = -2a(n-1)-4a(n-2). - R. J. Mathar, Feb 21 2008
MATHEMATICA
LinearRecurrence[{-2, -4}, {1, -4}, 30] (* Harvey P. Dale, Oct 05 2017 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Paul Barry, Feb 08 2008
STATUS
approved