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Template:Sequence of the Day for Thanksgiving

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Intended for: Thanksgiving Day, 2013, 2014, 2015, ...

Thanksgiving 2013 falls on November 28. The American observance calls for the fourth Thursday of November, and can thus be as "early" as the 22nd and as "late" as the 28th (the former when the month starts on a Thursday, the latter when the month starts on a Friday); thus roughly a month before Christmas, give or take a few days.

Timetable

  • First draft entered by Alonso del Arte on November 23, 2011
  • Draft reviewed by Daniel Forgues on November 24, 2011, November 25, 2019
  • Draft to be approved by October 28, 2013

Halloween's SOTD * Christmas's SOTD

The line below marks the end of the <noinclude>...</noinclude> section.



A000055: Number of trees with
n, n   ≥   0,
unlabeled nodes.
{ 1, 1, 1, 1, 2, 3, 6, 11, 23, 47, 106, 235, ... }

Trees with
n
unlabeled nodes[1]

n
Trees
0
 
Null tree
1
2
●—●
3
●—●—●
4
             ●
            /
●—●—●—●  ●—●  
            \
             ●
5
                 ●    ●
                /     |
●—●—●—●—●  ●—●—●    ●—●—●  
                \     |
                 ●    ●

This is the sequence for the example search on the front page of the OEIS. This Thanksgiving we are thankful for, among other things, the OEIS, which is an invaluable resource in many mathematical and scientific endeavors.

__________

  1. Weisstein, Eric W., Tree, from MathWorld—A Wolfram Web Resource.