Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 2,0,1,0,1 for x=0,1,2,3,4.

A197673

Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 2,0,1,0,1 for x=0,1,2,3,4.

Terms

    a(0) =1a(1) =9a(2) =57a(3) =1111a(4) =45162a(5) =4268977a(6) =924904506a(7) =452341382317

External references