1027080

Appears in sequences

• Number of weakly connected digraphs with n labeled nodes.at n=4A003027
• a(0)=a(1)=1. a(n) = the multiple of n which is > a(n-1)+a(n-2) and is <= a(n-1)+a(n-2)+n.at n=27A128034
• Triangular array read by rows. T(n,k) is the number of digraphs with n labeled nodes having exactly k undirected (or weak) components, n >= 1, 1 <= k <= n.at n=10A189898
• Square array A(n,k), n >= 1, k >= 1, read by antidiagonals, where column k is the expansion of e.g.f. log(Sum_{j>=0} k^binomial(j,2) * x^j/j!).at n=32A308460