1/4 the number of (n+1) X 9 binary arrays with equal numbers of 2 X 2 subblocks with sums 1 and 3.

A184603

1/4 the number of (n+1) X 9 binary arrays with equal numbers of 2 X 2 subblocks with sums 1 and 3.

Terms

    a(0) =10704a(1) =3333345a(2) =1339793447a(3) =586441134417

External references