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Curious if this function is called anything.

  1. Dec 24, 2013 #1
    Hey everyone, I was just playing around with factorial expansion and after grouping some terms I noticed a pattern for which I made a function. I am happy to provide more details as needed, but for now I have attached an image of the function and am curious, as per the title, whether this is known and if so if it has a name and/or interesting properties. I forgot to put this on the image but I was only considering positive naturals for a and n when defining the function.

    Thanks!
     

    Attached Files:

  2. jcsd
  3. Dec 24, 2013 #2
    Sorry, I should've posted this after working out the kinks. The a-n-1, a-n-2 part should be a-(n-1), a-(n-2), ... and k_n=n-1 should be k_n=n.
     
    Last edited: Dec 24, 2013
  4. Dec 24, 2013 #3

    Pythagorean

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  5. Dec 30, 2013 #4
    Actually, I figured out that these are (unsigned) Stirling numbers of the first kind (save where n=0), with 'a' being the rows of its pyramid, and 'n' being the column in each row. Ironic that I called the function S. I attached a simpler (and more accurate) version for anyone interested.
     

    Attached Files:

    Last edited: Dec 30, 2013
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