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A320575 a(n) gives the number of configurations of n non-attacking rooks on an n X n chessboard such that the number of distinct distances between the rooks is given by A319476(n). 6
1, 2, 6, 2, 2, 28, 2, 4, 2, 8, 4, 2, 2, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

For n = 7 the a(7) = 2 boards are mirror images of each other:

  +---+---+---+---+---+---+---+

7 |   |   | * |   |   |   |   |

  +---+---+---+---+---+---+---+

6 |   |   |   |   |   | * |   |

  +---+---+---+---+---+---+---+

5 | * |   |   |   |   |   |   |

  +---+---+---+---+---+---+---+

4 |   |   |   | * |   |   |   |

  +---+---+---+---+---+---+---+.

3 |   |   |   |   |   |   | * |

  +---+---+---+---+---+---+---+

2 |   | * |   |   |   |   |   |

  +---+---+---+---+---+---+---+

1 |   |   |   |   | * |   |   |

  +---+---+---+---+---+---+---+

    A   B   C   D   E   F   G

  +---+---+---+---+---+---+---+

7 |   |   |   |   | * |   |   |

  +---+---+---+---+---+---+---+

6 |   | * |   |   |   |   |   |

  +---+---+---+---+---+---+---+

5 |   |   |   |   |   |   | * |

  +---+---+---+---+---+---+---+

4 |   |   |   | * |   |   |   |

  +---+---+---+---+---+---+---+.

3 | * |   |   |   |   |   |   |

  +---+---+---+---+---+---+---+

2 |   |   |   |   |   | * |   |

  +---+---+---+---+---+---+---+

1 |   |   | * |   |   |   |   |

  +---+---+---+---+---+---+---+

    A   B   C   D   E   F   G

CROSSREFS

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

Sequence in context: A064136 A171898 A330541 * A110218 A316259 A057892

Adjacent sequences:  A320572 A320573 A320574 * A320576 A320577 A320578

KEYWORD

nonn,more

AUTHOR

Peter Kagey, Oct 15 2018

EXTENSIONS

a(10) corrected and a(11)-a(14) from Giovanni Resta, Oct 21 2018

STATUS

approved

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Last modified May 17 21:11 EDT 2021. Contains 343990 sequences. (Running on oeis4.)