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Number of ways of placing n nonattacking range-3 leprechauns on an n X n board.
1

%I #39 Oct 15 2021 03:46:11

%S 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,34,4,112,516,7312,81324,1056560,

%T 13443944,171919446,2195838076,28876216900,379982087060

%N Number of ways of placing n nonattacking range-3 leprechauns on an n X n board.

%C First 25 terms were computed by _Vaclav Kotesovec_ in 2020.

%C A range-k leprechaun is a fairy chess piece that can move to any square within range k, and to any square that a queen can move to (Escamocher and O'Sullivan 2021). A range-1 leprechaun is a queen, a range-2 leprechaun is a superqueen.

%H Guillaume Escamocher and Barry O'Sullivan, <a href="https://doi.org/10.1016/j.disc.2021.112316">Leprechauns on the chessboard</a>, Discrete Mathematics, 344(5), 2021.

%Y Cf. A000170, A051223, A343907.

%K nonn,more,hard

%O 1,16

%A _Guillaume Escamocher_, May 03 2021

%E a(26)-a(27) from _Martin Ehrenstein_, May 06 2021

%E a(26) confirmed by _Vaclav Kotesovec_, Jun 07 2021

%E a(28) from _Martin Ehrenstein_, Oct 14 2021