23679901

Appears in sequences

• Number of 2-colored connected labeled graphs with n vertices of the first color and n vertices of the second color.at n=4A005333
• Number of connected relations.at n=4A093732
• Triangle read by rows: T(n,k) = number of specially labeled bicolored connected graphs with k points in one color class and n-k points in the other class . "Special" means there are separate labels 1,2, ...,k and 1,2, ...,n-k for the two color classes (n >= 1, k = floor((n+1)/2), ..., n).at n=29A123260
• Leading diagonal of A123260.at n=9A123281
• T(n,k)=Number of nXk 0..4 arrays of sums of 2X2 subblocks of some (n+1)X(k+1) binary array.at n=24A226658
• Triangle read by rows: T(n, m) for 0 <= m <= n is the number of bipartite connected labeled graphs with parts of size n and m.at n=20A227322
• Array read by antidiagonals: T(m,n) = number of m X n binary matrices with all 1's connected and no zero rows or columns.at n=40A262307