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xkcd #3019: Advent Calendar Advent Calendar (xkcd.com)

submitted 3 weeks ago by schnurrito@discuss.tchncs.de to c/xkcd@lemmy.world

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The growth rate of items per day may may seem absurd, but it's actually much less than the acceleration in the 12 Days of Christmas song.

https://explainxkcd.com/3019/

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[–] Tudsamfa@lemmy.world 13 points 3 weeks ago (1 children)

(n*(n+1)/2 = 25*13 =325

Never mind the fact that the "correct" number of days on an advent calender is 24.

[–] Iron_Lynx@lemmy.world 2 points 3 weeks ago (1 children)

For one, it looks to me like the triangle numbers, which for triangle number T~n~ = (n+1) choose 2.

So for a correct nested advent calendar of 24 days, it's T~24~ = (24+1) choose 2 = 300

[–] Iron_Lynx@lemmy.world 2 points 3 weeks ago* (last edited 3 weeks ago)

Also, it appears that they created the terminal function that does that in a very compact notation, so another correct way to write down this sum is "24?" Where n? = n + (n-1)?