T(n,k)=Number of ways to arrange k nonattacking knights on the lower triangle of an n X n board.

Terms

a(0) =1a(1) =0a(2) =3a(3) =0a(4) =3a(5) =6a(6) =0a(7) =1a(8) =13a(9) =10a(10) =0a(11) =0a(12) =12a(13) =37a(14) =15a(15) =0a(16) =0a(17) =4a(18) =62a(19) =87a(20) =21a(21) =0a(22) =0a(23) =0a(24) =46a(25) =253a(26) =178a(27) =28a(28) =0a(29) =0