[seqfan] Swapping knights

Richard Guy rkg at cpsc.ucalgary.ca
Fri Oct 15 21:53:46 CEST 2010


I don't believe that the following sequence is in OEIS.

The (least) number of moves needed to swap
n  pairs of knights on a  3 by n  chessboard.

I.e., the number of chess knight moves needed
to get from

S  S  S  ...  S          s  s  s  ...  s
-  -  -       -    to    -  -  -       -
s  s  s  ...  s          S  S  S       S

where  s,  S  are chess knights of opposite
colors.  Not possible for  n = 1, 2, 3.

n = 4: 32 moves are necessary and sufficient.

n = 5, 6, 7, ... are Rikki-Tikki-Tavi questions
on p.250 (R187) of The Inquisitive Problem Solver.

R.




More information about the SeqFan mailing list