2,1

a(n) is union of A007582(n-1) and A164051(n). [From Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Aug 14 2009]

G.f.: x^2[3-x-6x^2]/[(1-2x)(1-2x^2)].

f := n->(2^n+2^floor(n/2))/2;

Equals (1/2) A005418(n+2). Cf. A056309, A052957.

Sequence in context: A154949 A107232 A134522 this_sequence A125750 A018168 A084321

Adjacent sequences: A001442 A001443 A001444 this_sequence A001446 A001447 A001448

nonn

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