Number of n X n 0..3 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

A203839

Number of n X n 0..3 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

Terms

    a(0) =1a(1) =4a(2) =262a(3) =84346a(4) =215340781

External references