A258110 - OEIS

%I #14 May 27 2015 15:44:29

%S 0,0,0,0,3,212,10592,449977,17727425,680781219,26046238416,

%T 1001222256515,38764377926857,1511202832516487

%N Number of Mirror Chess games that end in checkmate after exactly n moves.

%H J. Loy, <a href="https://web.archive.org/web/20130809093739/http://jimloy.com/chess/mirror1.htm">A Mirror Chess Problem</a>

%e a(4) = 3 because of these checkmates:

%e 1. c4 c5 2. Qa4 Qa5 3. Qc6 Qc3 4. Qxc8#

%e 1. d4 d5 2. Qd3 Qd6 3. Qh3 Qh6 4. Qxc8#

%e 1. d4 d5 2. Qd3 Qd6 3. Qf5 Qf4 4. Qxc8#

%Y Cf. A079485, A136257.

%K nonn,hard,more,fini

%O 0,5

%A _Jeremy Gardiner_, May 20 2015

%E a(5)-a(13) from _François Labelle_, May 25 2015