A352661 Number of doubly symmetric characteristic solutions to the n-superqueens problem.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 0, 0, 12, 17, 0, 0, 60, 82

Offset

1,12

Comments

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

References

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

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

Links

Table of n, a(n) for n=1..21.

Example

For n=12 the a(12)=2 solutions are
  +-------------------------+ +-------------------------+
  | . . . . A . . . . . . . | | . . . . A . . . . . . . |
  | . . . . . . . . . A . . | | . . . . . . . . . A . . |
  | . A . . . . . . . . . . | | . A . . . . . . . . . . |
  | . . . . . A . . . . . . | | . . . . . . A . . . . . |
  | . . . . . . . . . . . A | | . . . . . . . . . . . A |
  | . . . . . . . . A . . . | | . . . A . . . . . . . . |
  | . . . A . . . . . . . . | | . . . . . . . . A . . . |
  | A . . . . . . . . . . . | | A . . . . . . . . . . . |
  | . . . . . . A . . . . . | | . . . . . A . . . . . . |
  | . . . . . . . . . . A . | | . . . . . . . . . . A . |
  | . . A . . . . . . . . . | | . . A . . . . . . . . . |
  | . . . . . . . A . . . . | | . . . . . . . A . . . . |
  +-------------------------+ +-------------------------+

Crossrefs

A051224 = A352661 + A352662 + A352663.

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

Sequence in context: A337999 A037224 A122670 * A283494 A353254 A281034

Adjacent sequences: A352658 A352659 A352660 * A352662 A352663 A352664

Keyword

nonn,more

Author

Don Knuth, Mar 25 2022

Status

approved