Template:Did you know nominations/Telephone number (mathematics)

The following discussion is an archived discussion of the DYK nomination of the article below. Please do not modify this page. Subsequent comments should be made on the appropriate discussion page (such as this nomination's talk page, the article's talk page or Wikipedia talk:Did you know), unless there is consensus to re-open the discussion at this page. No further edits should be made to this page.

The result was: promoted by Crisco 1492 (talk) 14:46, 25 April 2012 (UTC)

Telephone number (mathematics)[edit]

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... that the number of ways to place n rooks on an n × n chessboard in such a way that no two rooks attack each other is a telephone number?

Created/expanded by David Eppstein (talk). Nominated by Carabinieri (talk) at 21:40, 30 March 2012 (UTC)

Thanks for the nom, but the hook is not quite accurate as stated. Without restriction, the number of placements is just a factorial; it needs diagonal symmetry to be a telephone number. How about:

ALT1 ... that the number of ways to place n diagonally-symmetric rooks on an n × n chessboard in such a way that no two rooks attack each other is a telephone number?

—David Eppstein (talk) 18:15, 2 April 2012 (UTC)

Sorry, I should've read the article more carefully.--Carabinieri (talk) 17:27, 3 April 2012 (UTC)

DYK criteria met. Going with ALT1. Cwmhiraeth (talk) 05:58, 25 April 2012 (UTC)