Template:Sequence of the Day for January 12

Intended for: January 12, 2012

Timetable

• First draft entered by Alonso del Arte on November 23, 2011 ✓
• Draft to be reviewed by November 12, 2011
• Draft to be approved by December 12, 2011

Yesterday's SOTD * Tomorrow's SOTD

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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

.