[seqfan] Re: Bad pdf file in A002369?

M. F. Hasler oeis at hasler.fr
Sun Feb 25 00:25:19 CET 2018


On Sat, Feb 24, 2018 at 4:01 PM, Richard J. Mathar <mathar at mpia-hd.mpg.de>
wrote:

> The construction of sequence A002369 is not clear to me either
> (probably because I don't understand the fine-tuned French).
>

The fine-tuned French says in particular, after the table of numbers,

*"Needless to say that the chances of errors are numerous in this kind of
work,*
*and we can only affirm the order of magnitude and not the exact figure*
*["digits of unity", literally]. Superfluous to add that we dont have the
general law."*

So IMHO there is non-negligible probability that this is just an erroneous
version of A056780.
Looking at the illustrations of initial terms shows that for n=4,
the
_XX
XX
polyomino is in both, but the
_X
XX
X
polyomino is only in A056780.
OTOH, the fact that XX and
X
X
are counted as different in both, makes me think that the omission of the
second 4-polyomino above is not intended.

- Maximilian


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