A320576 - OEIS

%I #9 Oct 22 2018 01:38:37

%S 1,1,2,1,1,10,1,1,1,1,1,1,1,1

%N a(n) gives the number of configurations of non-attacking rooks up to symmetry on an n X n chessboard such that the number of distinct distances between the rooks is given by A319476(n).

%H Giovanni Resta, <a href="/A320576/a320576.pdf">Illustration of a(3)-a(14)</a>

%e For n = 7 the a(7) = 1 board with A319476(7) = 5 distinct distances is

%e   +---+---+---+---+---+---+---+

%e 7 |   |   | * |   |   |   |   |

%e   +---+---+---+---+---+---+---+

%e 6 |   |   |   |   |   | * |   |

%e   +---+---+---+---+---+---+---+

%e 5 | * |   |   |   |   |   |   |

%e   +---+---+---+---+---+---+---+

%e 4 |   |   |   | * |   |   |   |

%e   +---+---+---+---+---+---+---+.

%e 3 |   |   |   |   |   |   | * |

%e   +---+---+---+---+---+---+---+

%e 2 |   | * |   |   |   |   |   |

%e   +---+---+---+---+---+---+---+

%e 1 |   |   |   |   | * |   |   |

%e   +---+---+---+---+---+---+---+

%e     A   B   C   D   E   F   G

%Y Cf. A319476, A320575, A320576, A320448, A320573, A320574.

%K nonn,more

%O 1,3

%A _Peter Kagey_, Oct 15 2018

%E a(10)-a(14) from _Giovanni Resta_, Oct 21 2018