1,2

G.f.: 4z(1+z)/[1-z+sqrt(1-2z-3z^2)]^2.

First differences of A005554. Partial sums of A026269.

Sequence in context: A086395 A020730 A003440 this_sequence A161943 A134184 A142975

Adjacent sequences: A102068 A102069 A102070 this_sequence A102072 A102073 A102074

nonn

Ralf Stephan, Dec 30 2004