Template:Sequence of the Day

[talk]

Sequence of the Day for January 12

A006967: Number of graceful permutations of length

n

.

{ 1, 2, 4, 4, 8, 24, 32, 40, 120, ... }

There are exactly

n!

permutations. But of those, only a few are graceful for

n > 2

.

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The following is in the <noinclude> ... </noinclude> section.

For more details about today's Sequence of the Day, see {{Sequence of the Day for January 12}}.

• To add a new entry, see Category:Sequence of the Day (future:no draft).
• To review an entry, see Category:Sequence of the Day (future:draft entered).
• To approve an entry, see Category:Sequence of the Day (future:draft reviewed).
• To view approved entries, see Category:Sequence of the Day (future:draft approved).

Guidelines for selecting the Sequence of the Day

• These are not rules. But if they were rules, they would only be enforced by the honor system.
• Whenever practical, the Sequence of the Day should bear some relation either to the calendar date (hint: browse arXiv e-prints by date) or to some recent newsworthy event.
• The write-up should be brief and not require advanced mathematical knowledge to understand.
• Positive preference given to sequences with keyword:nice.
• No special preference for sequences with keyword:core.
• Negative preference for sequences with keyword:uned or keyword:less. However, it is perfectly acceptable to polish up an uned sequence just prior to featuring.
• Each OEIS contributor should get at least one opportunity to choose the Sequence of the Day.
• The chooser ought not choose a sequence they have authored. But one they have edited heavily is perfectly acceptable.
• Ideally this will be changed each day at 0:00 per the OEIS Wiki clock. Each Sequence of the Day should be up for at least 22 hours but not more than 26 hours.
• There shouldn't be a big, heavy, bureaucratic apparatus to administer this feature.