Number of ways to place 6 nonattacking zebras on a 6 X n board.

Terms

a(0) =1a(1) =924a(2) =8989a(3) =37270a(4) =145233a(5) =525796a(6) =1605490a(7) =4136952a(8) =9435413a(9) =19632414a(10) =37957424a(11) =69050898a(12) =119351315a(13) =197524064a(14) =314935542a(15) =486171662a(16) =729604121a(17) =1068003424a(18) =1529198580a(19) =2146783422a(20) =2960869583a(21) =4018886128a(22) =5376425842