[seqfan] Re: Confused about A144204

Maximilian Hasler maximilian.hasler at gmail.com
Thu Jul 9 23:52:21 CEST 2009

> I looked up the fifth row and A144204 came up as a result.

There are indeed several errors in that sequence.

The data after (the first) "63" is a second copy of the preceding two
lines and should be deleted.

moreover the sequence shoud have the "tabl" keyword, to be formatted as

> But the
> definition for that sequence is "Arises in complete intersection
> threefolds, Array A[k,n] = (n+k-2)*(n-1) - 1 by antidiagonals." I'm
> not exactly sure how the formula (n + k - 2)(n - 1) - 1 gives the
> triangle quoted above. Just plugging it into the code above gives a
> somewhat different triangle. I do admit that I'm confused by

I think this formula is wrong, too.
It should be

  n + (k - 2)*(n - 1) - 2

* 1st parenthesis after n+, not before,
* and -2 in the end.

Then it gives the same as you have.


More information about the SeqFan mailing list