A352661 - OEIS

%I #28 Mar 29 2022 05:46:17

%S 0,0,0,0,0,0,0,0,0,0,0,2,2,0,0,12,17,0,0,60,82

%N Number of doubly symmetric characteristic solutions to the n-superqueens problem.

%C Superqueens are also called amazons. They combine the moves of queen and knight.

%D Martin Gardner, Fractal Music, Hypercards, and More, W H Freeman, 1991, page 238 (based on his column in Scientific American, June 1979).

%D D. E. Knuth, The Art of Computer Programming, Section 7.2.2.3 (draft, March 2022).

%e For n=12 the a(12)=2 solutions are

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

%e   | . . . . A . . . . . . . | | . . . . A . . . . . . . |

%e   | . . . . . . . . . A . . | | . . . . . . . . . A . . |

%e   | . A . . . . . . . . . . | | . A . . . . . . . . . . |

%e   | . . . . . A . . . . . . | | . . . . . . A . . . . . |

%e   | . . . . . . . . . . . A | | . . . . . . . . . . . A |

%e   | . . . . . . . . A . . . | | . . . A . . . . . . . . |

%e   | . . . A . . . . . . . . | | . . . . . . . . A . . . |

%e   | A . . . . . . . . . . . | | A . . . . . . . . . . . |

%e   | . . . . . . A . . . . . | | . . . . . A . . . . . . |

%e   | . . . . . . . . . . A . | | . . . . . . . . . . A . |

%e   | . . A . . . . . . . . . | | . . A . . . . . . . . . |

%e   | . . . . . . . A . . . . | | . . . . . . . A . . . . |

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

%Y A051224 = A352661 + A352662 + A352663.

%Y A051223 = 2*A352661 + 4*A352662 + 8*A352663 (when n>1).

%K nonn,more

%O 1,12

%A _Don Knuth_, Mar 25 2022