OFFSET
0,2
FORMULA
a(n)=A137717(n)/2^floor(n/2).
Empirical g.f.: -(4*x^3-4*x^2+4*x-1) / (4*x^4+2*x^2+1). - Colin Barker, Jun 27 2013
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, Feb 08 2008
STATUS
approved