1,2

a(n)=A008576(n-1), n>1. G.f.: x^2(3+2x+3x^2)/((1-x)^2*(1+x+x^2)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 18 2008]

Sequence in context: A137910 A022850 A008576 this_sequence A079392 A022852 A095375

Adjacent sequences: A047619 A047620 A047621 this_sequence A047623 A047624 A047625

nonn

N. J. A. Sloane (njas(AT)research.att.com).