OFFSET
0,2
COMMENTS
Hankel transform of A100095(n+1).
FORMULA
G.f.: (1+4x)/(1+4x^2); a(n)=2^n*(cos(pi*n/2)+2*sin(pi*n/2)).
a(n+3) = a(n+2)*a(n+1)/a(n). [Reinhard Zumkeller, Mar 04 2011]
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, Jun 05 2008
STATUS
approved