0,2

G.f.: (1-2x)/((1-2x)^2-3x^3); a(n)=sum{k=0..floor(n/3), binomial(n-k, 2k)3^k*2^(n-3k)}.

Cf. A099214.

Sequence in context: A052431 A076316 A082104 this_sequence A089407 A071115 A076317

Adjacent sequences: A099212 A099213 A099214 this_sequence A099216 A099217 A099218

easy,nonn

Paul Barry (pbarry(AT)wit.ie), Oct 06 2004