1/4 the number of n X n 0..3 symmetric matrices with every element equal to two or three horizontal and vertical neighbors.
A211083
1/4 the number of n X n 0..3 symmetric matrices with every element equal to two or three horizontal and vertical neighbors.
Terms
- a(0) =0a(1) =1a(2) =0a(3) =12a(4) =18a(5) =624a(6) =6012a(7) =228984a(8) =8210664a(9) =619049280a(10) =63783422784
External references
- oeis: A211083