2,1

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: A094986 A107232 A134522 this_sequence A125750 A018168 A084321

Adjacent sequences: A001442 A001443 A001444 this_sequence A001446 A001447 A001448

nonn

njas