A328816
Number of semi-magic (only short lines are magic) knight's tours on a 4 X 2n board.
Original entry on oeis.org
0, 0, 0, 16, 104, 608, 3480, 19212, 213280, 587072, 3237456
Offset: 1
Example of a 4 X 10 semi-magic knight's tour (only the short lines are magic):
+----+----+----+----+----+----+----+----+----+----+
| 1 | 38 | 3 | 24 | 5 | 34 | 9 | 26 | 13 | 30 |
+----+----+----+----+----+----+----+----+----+----+
| 20 | 23 | 18 | 37 | 8 | 25 | 6 | 29 | 10 | 27 |
+----+----+----+----+----+----+----+----+----+----+
| 39 | 2 | 21 | 4 | 33 | 16 | 35 | 12 | 31 | 14 |
+----+----+----+----+----+----+----+----+----+----+
| 22 | 19 | 40 | 17 | 36 | 7 | 32 | 15 | 28 | 11 |
+----+----+----+----+----+----+----+----+----+----+
A309271
Number of magic knight's tours on a 4 X 2n board.
Original entry on oeis.org
0, 0, 0, 0, 0, 0, 0, 0, 16, 88, 464, 2076, 9904, 47456
Offset: 1
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:
1 70 33 40 5 42 9 66 29 62 27 58 13 52 25 56 19 50
36 39 4 69 32 65 6 43 10 45 14 61 26 57 20 51 24 55
71 2 37 34 41 8 67 30 63 28 59 12 47 16 53 22 49 18
38 35 72 3 68 31 64 7 44 11 46 15 60 21 48 17 54 23
- M. Kraitchik, Mathematical Recreations, Dover, 1953, 257-266.
A328872
Number of semi-magic (only short lines are magic) knight's tours on a 6 X n board.
Original entry on oeis.org
0, 0, 0, 0, 0, 88, 288, 1880, 9994, 93718, 660282, 4310970
Offset: 1
Example 6 X 7 semi-magic knight's tour (only short lines are magic):
+----+----+----+----+----+----+----+
| 1 | 28 | 3 | 6 | 31 | 26 | 23 |
+----+----+----+----+----+----+----+
| 4 | 7 | 30 | 27 | 24 | 19 | 32 |
+----+----+----+----+----+----+----+
| 29 | 2 | 5 | 8 | 33 | 22 | 25 |
+----+----+----+----+----+----+----+
| 14 | 41 | 38 | 35 | 20 | 11 | 18 |
+----+----+----+----+----+----+----+
| 39 | 36 | 13 | 16 | 9 | 34 | 21 |
+----+----+----+----+----+----+----+
| 42 | 15 | 40 | 37 | 12 | 17 | 10 |
+----+----+----+----+----+----+----+
Showing 1-3 of 3 results.