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 A189876 Number of ways to place n nonattacking composite pieces queen + rider[2,3] on an n X n chessboard. 2
 1, 0, 0, 2, 10, 0, 0, 0, 0, 16, 60, 40, 304, 620, 2512, 8734, 28410, 94312, 345824, 1391072, 5759566, 25227796, 121663032, 635977968 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS (in fairy chess the rider [2,3] is called a Zebrarider) a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+2k)-p(i)|<>3k AND |p(j+3k)-p(j)|<>2k AND |p(m+k)-p(m)|<>k for all i>=1, j>=1, m>=1, k>=1, i+2k<=n, j+3k<=n, m+k<=n LINKS Table of n, a(n) for n=1..24. V. Kotesovec, Number of ways of placing non-attacking queens, kings, bishops and knights (in English and Czech) Wikipedia, Fairy chess piece CROSSREFS Cf. A102388, A189873, A189854 Sequence in context: A120314 A050924 A181500 * A189867 A189875 A189866 Adjacent sequences: A189873 A189874 A189875 * A189877 A189878 A189879 KEYWORD nonn,hard AUTHOR Vaclav Kotesovec, Apr 29 2011 STATUS approved

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Last modified August 9 20:04 EDT 2024. Contains 375044 sequences. (Running on oeis4.)