A308312 - OEIS

A308312

a(n) is the last square visited by knight moves on a spirally numbered (2n-1) X (2n-1) board, moving to the lowest available unvisited square at each step.

%I #19 Jul 23 2019 21:10:03

%S 1,1,14,30,69,108,150,205,264,333,408,475,553,659,763,881,1004,1134,

%T 1274,1418,1641,1811,1986,2167,2358,2557,2633,2978,2084,2084,2084,

%U 2084,2084,2084,2084,2084,2084,2084,2084,2084,2084,2084,2084,2084,2084,2084,2084

%N a(n) is the last square visited by knight moves on a spirally numbered (2n-1) X (2n-1) board, moving to the lowest available unvisited square at each step.

%C A 5 X 5 board, for example, is numbered with the square spiral:

%C .

%C 21--22--23--24--25

%C |

%C 20 7---8---9--10

%C | | |

%C 19 6 1---2 11

%C | | | |

%C 18 5---4---3 12

%C | |

%C 17--16--15--14--13

%C .

%C a(n) stays constant at 2084 for (2n-1) >= 57 since 2084 is also the last square visited by knight moves on a spirally numbered doubly infinite board, moving to the lowest available unvisited square at each step.

%Y Cf. A316667.

%K nonn

%O 1,3

%A _Sangeet Paul_, May 19 2019