Half the number of (n+1) X (n+1) symmetric 0..3 arrays with no 2 X 2 subblock summing to 6.

A213692

Half the number of (n+1) X (n+1) symmetric 0..3 arrays with no 2 X 2 subblock summing to 6.

Terms

    a(0) =28a(1) =1320a(2) =208072a(3) =109820000a(4) =193946752094

External references