A323471 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.

-1, 2084, 7081, 10847, 25963, 22421, 202891, 142679, 252953, 188501, 257479, 604328, 667827, 57217, 115497, 231930, 203331, 283651, 426851, 153521, 231299, 142267, 236487, 149872, 204527, 215033, 285983, 188082, 153461, 128802, 213853, 202259, 94967, 224778

Offset: 1

Author

N. J. A. Sloane, Jan 28 2019

Keywords

• sign

Comments

A (1,2) leaper is a chess knight.

a(2)-a(5) were computed by Daniël Karssen.

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..1000
• N. J. A. Sloane and Brady Haran, The Trapped Knight, Numberphile video (2019)

Crossrefs

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.

Extensions

More terms from Rémy Sigrist, Jan 29 2019