127756

Appears in sequences

• Total number of interior nodes in all essentially series series-parallel networks with n labeled edges, multiple edges allowed.at n=7A058478
• a(n) = A080313(n)/2.at n=21A080315
• a(n) = Sum_{k=0..n} (-1)^k * (3*k+1) * binomial(4*n-k+1,n-k)/(4*n-k+1).at n=8A390500