0,2

2[ (n+2)/4 ] if n even, 2[ (n+1)/4 ]+1 if n odd (n >= 8).

G.f.: x(3-x+x^2-x^3-2x^4+2x^5)/((1-x)^2*(1+x)(1+x^2)). a(n)=A083219(n), n<>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 15 2008]

Sequence in context: A095206 A049071 A029211 this_sequence A097618 A039639 A023509

Adjacent sequences: A018834 A018835 A018836 this_sequence A018838 A018839 A018840

nonn,easy

N. J. A. Sloane (njas(AT)research.att.com), Marc LeBrun (mlb(AT)well.com)