%N On a spirally numbered chessboard, with labels starting at 1, this is the number of steps that a (1,n) leaper makes before getting trapped, or -1 if it never gets trapped.
%C A (1,2) leaper is a chess knight.
%C a(2)-a(5) were computed by _Daniël Karssen_.
%H Rémy Sigrist, <a href="/A323469/b323469.txt">Table of n, a(n) for n = 1..1000</a>
%H Neil Sloane and Brady Haran, <a href="https://www.youtube.com/watch?v=RGQe8waGJ4w">The Trapped Knight</a>, Numberphile video (2019)
%Y The sequences involved in this set of related sequences are A316884, A316967, A316667, A316328, A317106, A317105, A317416, A317415, A317438, A317437, and A323469, A323470, A323471, A323472.
%A _N. J. A. Sloane_, Jan 28 2019
%E More terms from _Rémy Sigrist_, Jan 29 2019