Number of ways to place 4 nonattacking wazirs on a 4 X n board.

Terms

a(0) =0a(1) =2a(2) =61a(3) =405a(4) =1502a(5) =4072a(6) =9091a(7) =17791a(8) =31660a(9) =52442a(10) =82137a(11) =123001a(12) =177546a(13) =248540a(14) =339007a(15) =452227a(16) =591736a(17) =761326a(18) =965045a(19) =1207197a(20) =1492342a(21) =1825296a(22) =2211131a(23) =2655175a(24) =3163012a(25) =3740482a(26) =4393681a(27) =5128961a(28) =5952930a(29) =6872452