[seqfan] Re: OEIS Wiki: Offsets

M. F. Hasler oeis at hasler.fr
Mon Apr 13 22:10:48 CEST 2015


On Mon, Apr 13, 2015 at 12:45 PM, Alonso Del Arte
<alonso.delarte at gmail.com> wrote:
> I do like how Felix elaborated the offset 3 example.

I also appreciate the wish to make things, which are obscure for many
OEIS users, more explicit.

But I also agree with the rule :

>> "Think long and hard whether a(0) is naturally defined. If yes, add it."


>> The old text was shorter and clearer as well.

shorter yes, but I think it's worth while adding examples.

but regarding these, I ran into contradictions.
E.g, the Planck time 5x10^-44 is cited for offset -44, but actually
the offset is currently (maybe wrongly) -43.
Personally, I think the current conventions for offset & indices for
constants are a source of eternal confusion, it would be so simple and
consistent to say that c = sum( i >= offset, a(i)*10^-i )
[indices would be growing to +oo everywhere and would be equal to the
position of the digit in the decimals of the number, which would be so
natural...]
but instead there are sometimes indices going from  offset  to  - oo
(as they "should"), but sometimes (in the b-files and/or "list" page,
IIRC the one shows the opposite of the other) they grow from offset to
+oo, etc...
What is more, there is no reasonable display of the constants ; if you
click "constant" on the Planck time, if at least it would show
5.39... x 10 ^ -44  or  0.539... x 10 ^ -43
or something alike, this would help. But currently it shows :  539106


Back to the original subject, I think it is worth while mentioning the
example of sets & lists, and also insist on the example of general
functions defined from some given value on (which may be more often 0
than 1, but also something else).

--Maximilian



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