OFFSET
0,4
COMMENTS
A Chebyshev transform of A052947, which has g.f. 1/(1-x^2-2x^3). The image of G(x) under the Chebyshev transform is (1/(1+x^2))G(x/(1+x^2)).
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,-2,2,-2,0,-1).
FORMULA
G.f.: (1+x^2)^2/(1+2x^2-2x^3+2x^4+x^6); a(n)=-2a(n-2)+2a(n-3)-2a(n-4)-a(n-6); a(n)=sum{k=0..floor(n/2), C(n-k, k)(-1)^k*sum{j=0..floor((n-2k)/2), C(j, n-2k-2j)2^(n-2k-2j)}}.
MATHEMATICA
LinearRecurrence[{0, -2, 2, -2, 0, -1}, {1, 0, 0, 2, -1, -4}, 50] (* Harvey P. Dale, Dec 20 2015 *)
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, Oct 19 2004
STATUS
approved