Number of n X n symmetric 0..3 arrays with rows, considered as 4-ary numbers, in strictly increasing order.

A162128

Number of n X n symmetric 0..3 arrays with rows, considered as 4-ary numbers, in strictly increasing order.

Terms

    a(0) =4a(1) =30a(2) =720a(3) =53505a(4) =12680820a(5) =9936894780

External references