19646

Appears in sequences

• a(n) = [ 3rd elementary symmetric function of {log(k)} ], k = 2,3,...,n.at n=19A025203
• Triangle of number of (weakly) connected unlabeled digraphs with n nodes and k arcs (n >=2, k >= 1).at n=48A054733
• a(n) = Sum_{k=0..n} F(n+k)*binomial(n+k,k) where F=A000045.at n=5A118726
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (-1, 1), (0, 1), (1, -1)}.at n=12A151390
• Irregular triangular array read by rows: T(n,k) is the number of non-isomorphic unlabeled weakly connected digraphs on n nodes and with k arcs.at n=39A283753
• Triangle read by rows: T(n,k) is the number of unlabeled weakly connected digraphs with n arcs and k vertices, k = 1..n+1.at n=50A350789
• Expansion of (1/x) * Series_Reversion( x * (1-x) * (1-x^3)^2 ).at n=9A369296