cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A323838 Number of (2n+1) X (2n+1) black-and-white grids that are legal for crossword puzzles.

Original entry on oeis.org

1, 15, 397, 35324, 18446134, 41752489852, 409764131469787, 17368974525101032256, 3195393813996265512672344, 2544868518166378264304163732974
Offset: 1

Views

Author

N. J. A. Sloane, Feb 04 2019

Keywords

Comments

Rules: Every white square must be "checked" (in both a horizontal and vertical word), words must be at least 3 letters long, the whole grid must be symmetric under 180-degree rotation, and the set of white squares must be connected.
Computed by Michael Kleber.

References

  • Michael Kleber, Posting to Math Fun Mailing List, Feb 04 2019.

Crossrefs

Cf. A323839, A325408, A325409.
There are many other OEIS sequences related to crossword puzzles: search for "crossword puzzle" (without the quotes).

Extensions

a(4)-a(7) corrected by Michael Kleber, Feb 06 2019
a(8)-a(10) added by Michael Kleber, Apr 23 2019

A323839 Number of (2n+1) X (2n+1) black-and-white grids that are legal for crossword puzzles and have no all-black edges.

Original entry on oeis.org

1, 12, 312, 31187, 17438702, 40575832476, 404139015237875, 17253201646564115439, 3185118492387669085270268, 2540927098290913247876202007100
Offset: 1

Views

Author

N. J. A. Sloane, Feb 04 2019

Keywords

Comments

Rules: Every white square must be "checked" (in both a horizontal and vertical word), words must be at least 3 letters long, the whole grid must be symmetric under 180-degree rotation, and the set of white squares must be connected.
Computed by Michael Kleber.

References

  • Michael Kleber, Posting to Math Fun Mailing List, Feb 04 2019.

Crossrefs

Cf. A323838, A325408, A325409
There are many other OEIS sequences related to crossword puzzles: search for "crossword puzzle" (without the quotes).

Extensions

a(4)-a(7) corrected by Michael Kleber, Feb 06 2019
a(8)-a(10) added by Michael Kleber, Apr 23 2019

A325409 Number of (2n+1) X (2n+1) black-and-white mirror-symmetric grids that are legal for crossword puzzles and have no all-black edges.

Original entry on oeis.org

1, 2, 20, 269, 8116, 519400, 67566361, 17518353991, 9334778743018, 10240638005472594, 23244895727823155064
Offset: 1

Views

Author

Michael Kleber, Apr 23 2019

Keywords

Comments

Rules: Every white square must be "checked" (in both a horizontal and vertical word), words must be at least 3 letters long, the whole grid must be symmetric under both left-right and top-bottom mirror symmetry, and the set of white squares must be connected.

Crossrefs

Cf. A323838, A323839, A325408.
There are many other OEIS sequences related to crossword puzzles: search for "crossword puzzle" (without the quotes).

Extensions

a(11) added by Akshay Ravikumar, Jun 20 2019
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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