[seqfan] Re: Polyominoes (A000105, A000988, A001168) - offset problem

[Brendan McKay]

Hi Neil,

Anyone who sees an error on Wikipedia, and knows how to fix it but 
doesn't, is
responsible for the error.

But in this case there is no error.  Wikipedia follows "reliable 
sources" and in this case
the reliable source is Golumb's book "Polyominoes".  From a brief look 
it seems that
Golumb does not recognise a null polyomino (see Fig 1 and Tables 3 and 
D.1), so
Wikipedia is *required* to either also disallow it or to change to a 
different source.

Incidentally, the first comment on A0000105, which is
"A0000105(n) + A030228(n) = A000988(n)", is not correct for n=0 at the 
moment.

Cheers, Brendan.

On 25/6/20 5:27 pm, Neil Sloane wrote:
> Everything in the Wikipedia is inaccurate.