[seqfan] Numbers of the form n*(n+k)

MARION charliemath at optonline.net
Thu Mar 19 15:33:22 CET 2020


Dear SeqFans,

I have a question regarding terminology.

We call the terms of A000290   0, 1, 4, 9, ...  the (perfect) squares.

We call the terms of A002378   0, 2, 6, 12 ... the oblongs.

What do we call the terms of A005563  0, 3, 8, 15?

What do we call the terms of A028552  0, 4, 10, 18?

What do you think about calling them the +2products and +3products, respectively?  Thus, the squares would be the +0products and the oblongs, the +1products.  Note that I'm not advocating changing the way we refer to the squares or the oblongs.  I'm simply looking for another way to refer to the terms in sequences like A005563 and A028552.

I would like to call them something other than "the numbers of the form n*(n+2)" or "the numbers of the form n*(n+3)."  Perhaps I'm just not aware of some other "shortcut."

Thanks for any feedback,

Charlie Marion

Yorktown Heights New York




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