Number of (directed) Hamiltonian paths in the 3 X n knight graph.

Terms

a(0) =0a(1) =0a(2) =0a(3) =16a(4) =0a(5) =0a(6) =104a(7) =792a(8) =1120a(9) =6096a(10) =21344a(11) =114496a(12) =257728a(13) =1292544a(14) =3677568a(15) =17273760a(16) =46801984a(17) =211731376a(18) =611507360a(19) =2645699504a(20) =7725948608a(21) =32451640000a(22) =97488160384a(23) =397346625760