42148

Appears in sequences

• Triangle of number of (weakly) connected unlabeled digraphs with n nodes and k arcs (n >=2, k >= 1).at n=49A054733
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, -1), (-1, 0, 1), (1, 0, 0), (1, 1, -1)}.at n=11A148227
• Numbers n such that prime(n) + reversal(prime(n)) is a square.at n=39A227371
• 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=40A283753