5581315

Appears in sequences

• a(n) = 7^n - 3*4^n + 2*3^n.at n=7A002501
• 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=37A123260
• 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=29A226658