Number of geometrically distinct open knight's tours of a 3 X n chessboard that have twofold symmetry.

A169776

Number of geometrically distinct open knight's tours of a 3 X n chessboard that have twofold symmetry.

Terms

    a(0) =2a(1) =0a(2) =0a(3) =2a(4) =10a(5) =12a(6) =22a(7) =60a(8) =76a(9) =160a(10) =292a(11) =652a(12) =1148a(13) =2600a(14) =3870a(15) =9152a(16) =13710a(17) =32792a(18) =48112a(19) =116624a(20) =171732a(21) =428064a(22) =589842a(23) =1496508a(24) =2069766a(25) =5348640a(26) =7164172a(27) =18742712a(28) =25160796a(29) =66758832

External references