Number of n X n symmetric 0..1 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..1 introduced in lower triangular row major order.

A192995

Number of n X n symmetric 0..1 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..1 introduced in lower triangular row major order.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =5a(4) =24a(5) =184a(6) =2052a(7) =34481a(8) =852317a(9) =31436448a(10) =1719054683a(11) =139749375352

External references