Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no element equal to more than one horizontal or vertical neighbor.

A194535

Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no element equal to more than one horizontal or vertical neighbor.

Terms

    a(0) =1a(1) =4a(2) =116a(3) =16556a(4) =7721920a(5) =11525456507

External references