1,1

Contribution from Paul Barry (pbarry(AT)wit.ie), Sep 01 2009: (Start)

G.f.: (2+x+x^2+2x^3)/(1-x-x^3+x^4);

a(n)=1+2n+cos(2*pi*n/3)+sin(2*pi*n/3)/sqrt(3). (End)

Sequence in context: A069811 A004826 A132115 this_sequence A032968 A080823 A079279

Adjacent sequences: A047225 A047226 A047227 this_sequence A047229 A047230 A047231

nonn

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