1,1

a(2n+1)=A016825(n). a(2n)=A016825(n+1).

G.f.: 2x(1+4x-4x^2)/((1+x)(1-x)^2)). a(n)=a(n-1)+a(n-2)-a(n-3) = 2n+3+3*(-1)^n = 2*A097062(n+2). - R. J. Mathar, Oct 24 2008

Sequence in context: A105801 A086064 A076374 this_sequence A082225 A037187 A166542

Adjacent sequences: A142951 A142952 A142953 this_sequence A142955 A142956 A142957

nonn

Paul Curtz (bpcrtz(AT)free.fr), Sep 29 2008

Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 24 2008