Number of 4-step king's tours on an n X n board summed over all starting positions.

Terms

a(0) =0a(1) =24a(2) =496a(3) =1764a(4) =3768a(5) =6508a(6) =9984a(7) =14196a(8) =19144a(9) =24828a(10) =31248a(11) =38404a(12) =46296a(13) =54924a(14) =64288a(15) =74388a(16) =85224a(17) =96796a(18) =109104a(19) =122148a(20) =135928a(21) =150444a(22) =165696a(23) =181684a(24) =198408a(25) =215868a(26) =234064a(27) =252996a(28) =272664a(29) =293068