%I #11 Apr 30 2021 21:25:35
%S -1,2084,7081,10847,25963,22421,202891,142679,252953,188501,257479,
%T 604328,667827,57217,115497,231930,203331,283651,426851,153521,231299,
%U 142267,236487,149872,204527,215033,285983,188082,153461,128802,213853,202259,94967,224778
%N On a spirally numbered square grid, with labels starting at 1, this is the number of the last cell that a (1,n) leaper reaches 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="/A323471/b323471.txt">Table of n, a(n) for n = 1..1000</a>
%H N. J. A. 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.
%K sign
%O 1,2
%A _N. J. A. Sloane_, Jan 28 2019
%E More terms from _Rémy Sigrist_, Jan 29 2019