1/4 the number of colorings of an n X n rhombic hexagonal array with 4 colors.

A068271

1/4 the number of colorings of an n X n rhombic hexagonal array with 4 colors.

Terms

    a(0) =1a(1) =12a(2) =264a(3) =11424a(4) =1008576a(5) =184910592a(6) =71033971200

External references