53049

Appears in sequences

• Numbers k such that 2*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=18A056700
• Number of (4+1) X (n+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.at n=12A250759
• Number of connected 2n-regular loopless multigraphs with five nodes.at n=24A324221