A244284 Number of ways to place n nonattacking zebras on an n X n chessboard.

1, 6, 84, 1168, 20502, 525796, 18939708, 802444170, 38934305898, 2170312156170, 138154298519618, 9880410074942146, 782899186307621151, 68058665346833701338, 6442021882892718443852

Offset

1,2

Comments

Zebra is a (fairy chess) leaper [2,3].

Links

Table of n, a(n) for n=1..15.

V. Kotesovec, Non-attacking chess pieces, 6ed, 2013, p.363

Wikipedia, Fairy chess piece

Formula

a(n) ~ n^(2*n)/n! * exp(-9/2).

Crossrefs

Cf. A172137, A172138, A172139, A172140.

Cf. A201540, A201511, A201861, A201513.

Sequence in context: A212701 A248338 A144514 * A011945 A113888 A163947

Adjacent sequences: A244281 A244282 A244283 * A244285 A244286 A244287

Keyword

nonn,hard,more

Author

Vaclav Kotesovec, Jun 25 2014

Extensions

a(11)-a(15) from Martin Fuller, Mar 24 2026

Status

approved