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A189856 Number of ways to place n nonattacking composite pieces rook + rider[2,5] on an n X n chessboard. 4

%I #6 Sep 12 2015 11:00:25

%S 1,2,6,24,120,392,1810,10400,72228,589674,3823906,29420944,266232984,

%T 2711139976,30669073348,316482938974

%N Number of ways to place n nonattacking composite pieces rook + rider[2,5] on an n X n chessboard.

%C a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+2k)-p(i)|<>5k AND |p(j+5k)-p(j)|<>2k for all i>=1, j>=1, k>=1, i+2k<=n, j+5k<=n

%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens, kings, bishops and knights</a> (in English and Czech)

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a>

%Y Cf. A000170, A189854, A189855

%K nonn,hard

%O 1,2

%A _Vaclav Kotesovec_, Apr 29 2011

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Last modified September 10 04:30 EDT 2024. Contains 375773 sequences. (Running on oeis4.)