Number of lower triangles of an n X n 0..4 array with each element equal to the number of its horizontal and vertical neighbors unequal to itself.

A195952

Number of lower triangles of an n X n 0..4 array with each element equal to the number of its horizontal and vertical neighbors unequal to itself.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =3a(4) =3a(5) =8a(6) =3a(7) =33a(8) =62a(9) =161a(10) =137a(11) =1336a(12) =2528a(13) =8851a(14) =25727a(15) =92540a(16) =377525a(17) =1909048

External references