Number of point symmetric solutions to non-attacking queens problem on n X n board.

Terms

a(0) =1a(1) =0a(2) =0a(3) =2a(4) =2a(5) =4a(6) =8a(7) =4a(8) =16a(9) =12a(10) =48a(11) =80a(12) =136a(13) =420a(14) =1240a(15) =3000a(16) =8152a(17) =18104a(18) =44184a(19) =144620a(20) =375664a(21) =1250692a(22) =3581240a(23) =11675080a(24) =34132592a(25) =115718268a(26) =320403024a(27) =1250901440a(28) =3600075088a(29) =14589438024