Number of 2n X 2n addition squares in which every digram (s,s;), s' != s, appears once horizontally and once vertically.

A238838

Number of 2n X 2n addition squares in which every digram (s,s;), s' != s, appears once horizontally and once vertically.

Terms

    a(0) =2a(1) =48a(2) =5760a(3) =5806080a(4) =75246796800

External references