%I #25 Feb 01 2022 00:29:20
%S 0,0,0,0,0,0,0,0,16,88,464,2076,9904,47456
%N Number of magic knight's tours on a 4 X 2n board.
%D M. Kraitchik, Mathematical Recreations, Dover, 1953, 257-266.
%H G. P. Jelliss, <a href="http://www.mayhematics.com/t/mo.htm">Oblong Magic Knight Tours</a>
%H Awani Kumar, <a href="https://arxiv.org/abs/1802.09340">Studies in Tours of Knight on Rectangular Boards</a>, arXiv:1802.09340 [math.GM], 2018.
%e An example of a magic knight's tour on a 4 X 18 board. All rows sum to 657 and all columns sum to 146:
%e 1 70 33 40 5 42 9 66 29 62 27 58 13 52 25 56 19 50
%e 36 39 4 69 32 65 6 43 10 45 14 61 26 57 20 51 24 55
%e 71 2 37 34 41 8 67 30 63 28 59 12 47 16 53 22 49 18
%e 38 35 72 3 68 31 64 7 44 11 46 15 60 21 48 17 54 23
%Y Cf. A079137, A123936, A309273.
%K nonn,more
%O 1,9
%A _Awani Kumar_, Jul 20 2019