260 (number)

260 (two hundred [and] sixty) is the magic constant of nxn magic square and n-Queens Problem for n = 8, the size of an actual chess board.

260 is also the magic constant of the Franklin magic square devised by Benjamin Franklin.

52 61  4 13 20 29 36 45
14  3 62 51 46 35 30 19
53 60  5 12 21 28 37 44
11  6 59 54 43 38 27 22
55 58  7 10 23 26 39 42
 9  8 57 56 41 40 25 24
50 63  2 15 18 31 34 47
16  1 64 49 48 33 32 17

The minor diagonal gives 260, an in addition a number of combinations of two half diagonals of four numbers from a corner to the center give 260.

In other fields

260 is also:

• Given a 4 by 4 chessboard, there are only 260 ways to place six non-attacking bishops.
• The year AD 260 and 260 BC.