Number of n X n 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.

A303720

Number of n X n 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.

Terms

    a(0) =1a(1) =8a(2) =23a(3) =84a(4) =219a(5) =569a(6) =1476a(7) =3614a(8) =8730a(9) =20886a(10) =49351a(11) =114833a(12) =265877a(13) =610405a(14) =1396025a(15) =3172297a(16) =7195606a(17) =16230944a(18) =36563883a(19) =82008735a(20) =183813328a(21) =410490052

External references