OFFSET
1,2
COMMENTS
Given an n X n chessboard, this sequence is the maximum number of knights that can be placed on the board, such that each knight has a free path to jump "off" the board without another knight moving.
An example for a(3):
XXX
XXX
XXX
Here, all knights can jump off the board via knight movement. The middle knight is not blocked by any pieces.
An example for a(5):
XXXXX
XXXXX
XX-XX
XXXXX
XXXXX
Here, a knight can occupy all spaces except the central space, where a knight would not be able to jump off the board and would not be able to jump to another free square.
LINKS
Nicholas Tran, Solution in ASP
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Nicholas Tran, Sep 17 2020
STATUS
approved