Number of n X n symmetric 0..6 arrays with each element equal to at least one horizontal or vertical neighbor and any new values 0..6 introduced in lower triangular row major order.
A192643
Number of n X n symmetric 0..6 arrays with each element equal to at least one horizontal or vertical neighbor and any new values 0..6 introduced in lower triangular row major order.
Terms
- a(0) =0a(1) =1a(2) =5a(3) =137a(4) =17687a(5) =14704140a(6) =73684193256
External references
- oeis: A192643