[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
http://www.research.att.com/~njas/sequences/table?a=144204&fmt=123
> 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
i.e.
* 1st parenthesis after n+, not before,
* and -2 in the end.
Then it gives the same as you have.
Maximilian
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