OFFSET
0,5
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,-1,-2,-2,0,-1).
FORMULA
a(n) = 2*a(n-1) - a(n-2) - 2*a(n-3) - 2*a(n-4) - a(n-6).
a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(2*n-4*k,2*k).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec((1-x+x^3)/((1-x+x^3)^2+4*x^4))
(PARI) a(n) = sum(k=0, n\3, (-1)^k*binomial(2*n-4*k, 2*k));
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 10 2024
STATUS
approved