OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (-2,0,-2).
FORMULA
a(n) = (-1)^n*Sum_{k=0..n} C(n-k,floor(k/2))*2^(n-k). - Paul Barry, Oct 20 2009
a(0) = 1, a(1) = -3, a(2) = 6, a(n) = -2*a(n-1) - 2*a(n-3) for n > 2. - Jinyuan Wang, Apr 07 2020
PROG
(PARI) Vec((1-x)/(1+2*x+2*x^3) + O(x^50)) \\ Jinyuan Wang, Apr 07 2020
CROSSREFS
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved