Number of n X n symmetric 0..1 arrays with each element equal to at least two horizontal or vertical neighbors, containing at least one 1 and with new values 0..1 introduced in lower triangular row major order.
A192840
Number of n X n symmetric 0..1 arrays with each element equal to at least two horizontal or vertical neighbors, containing at least one 1 and with new values 0..1 introduced in lower triangular row major order.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =4a(4) =23a(5) =183a(6) =2051a(7) =34480a(8) =852316a(9) =31436447a(10) =1719054682a(11) =139749375351
External references
- oeis: A192840