OFFSET
0,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,2,2,-1,2,-1).
FORMULA
a(n) = 2*a(n-2) + 2*a(n-3) - a(n-4) + 2*a(n-5) - a(n-6).
a(n) = Sum_{k=0..floor(n/2)} binomial(2*k+1,2*n-4*k+1).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec((1+x^2-x^3)/((1+x^2-x^3)^2-4*x^2))
(PARI) a(n) = sum(k=0, n\2, binomial(2*k+1, 2*n-4*k+1));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 03 2024
STATUS
approved