1/32 the number of (n+1) X 9 binary arrays with equal numbers of 2 X 2 subblocks with sum mod two being 0 and 1.

A183771

1/32 the number of (n+1) X 9 binary arrays with equal numbers of 2 X 2 subblocks with sum mod two being 0 and 1.

Terms

    a(0) =2240a(1) =823680a(2) =346131968a(3) =153876579840

External references