0,7

E. Barcucci, E. Pergola, R. Pinzani and S. Rinaldi, ECO method and hill-free generalized Motzkin paths

G.f.: [1-x^3+2x^2-sqrt(1-2x^3+x^6-4x^2)]/[2x^2*(2+x^2-x^3)].

Cf. A001003, A089372, A099171.

Sequence in context: A127904 A048578 A087312 this_sequence A018095 A003217 A006723

Adjacent sequences: A099167 A099168 A099169 this_sequence A099171 A099172 A099173

nonn

Ralf Stephan, Oct 09 2004