Number of ways to place 3 nonattacking nightriders on an n X n cylindrical board.

Terms

a(0) =0a(1) =0a(2) =6a(3) =144a(4) =600a(5) =1992a(6) =4592a(7) =15616a(8) =31788a(9) =74840a(10) =122210a(11) =251184a(12) =384826a(13) =647696a(14) =1085190a(15) =1616384a(16) =2308872a(17) =3449880a(18) =4783326a(19) =7052400a(20) =9253734a(21) =12454640a(22) =16453096a(23) =22180992a(24) =28552450a(25) =36216544a(26) =46089162a(27) =58449104a(28) =72061346a(29) =91140000