Equals two maps: number of n X n binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 n X n array.

A221287

Equals two maps: number of n X n binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 n X n array.

Terms

    a(0) =1a(1) =4a(2) =92a(3) =9107a(4) =4983598a(5) =10344276279

External references