non-duplicates that should be duplicates

[Maximilian Hasler]

Well, 347 is certainly a misspelling of 374,
and it's certainly interesting to record these years in OEIS but this
might be frowned upon for different reasons :

* we just noticed the problem of -1 = 1BC being the year that precedes
1AD (although both enries say "negative means BC")

* calendars changed often, so how is the beginning of a year defined ?

* what means "recorded observation" ?  I'm sure sooner or later a
record dating before "-240" (whatever that means) mentioning that
comet will be found

* still, if the recorded years were those of the perihelion or closest
point to earth (I believe these could be calculated with sufficient
precision - ), but to put the year of observation ? in particular if
the appearance is close to end/beginning of some year...?

* Citation from http://www.geocities.com/Athens/Olympus/6745/HalleyFAQs.htm :
..., in 1985 it was best visible in November and December on the way
in, and then it was visible again in March and April, 1986 ...

So 1985 and 1986 should both figure in the sequence, according to the
definition  of

A072235  	 	 Years of recorded observations of Comet Halley.

* also, in the comment of that seqeunce, " I do not know if these
years necessarily coincide with actual years of perihelion."
In fact, these two dates can differ by several months, and thus
frequently correspond to different years.

In order for OEIS to remain a scientific reference data base, /at
least/ all these possible "imprecisions" should be explicitely
mentioned (in that A072235 is better than A100748).
Maybe also a special tag (keyword) for "non-mathematical sequences"
should be added... (why not keyword "year" - implicitely containing
many of the preceding problems concerning accuracy, inherent to all
listings of years)

M.H.



Max,   thanks for those comments!

May I make a request?

Here is what you sent me:

> Please extend A093151 as follows:
> 
> 1, 13, 169, 1890, 20216, 210824, 2167819, 22119495, 224576508, 2272476724, 22940979719, 231196075659, 2326967290816, 23397529216327, 235077715264515, 2360380831212204
> 
> and add a formula:
> 
> %F A093151 a(n) = 25*10^(n-2) - 1 - A091098(n)


If you would use the following format it would
of editing errors:

%I A093151
%S A093151 1, 13, 169, 1890, 20216, 210824, 2167819, 22119495,
224576508, 2272476724, 22940979719, 231196075659, 2326967290816, 23397529216327, 235077715264515, 2360380831212204
%C A093151 More terms, formula
%F A093151 a(n) = 25*10^(n-2) - 1 - A091098(n)
%A A093151 Max Alekseyev <maxal at cs.ucsd.edu>, May 30 2007

Then my editing programs do all the work.  Otherwise I have
to cut and paste by hand.

Thanks!

Neil

(I will copy this to the seqfan list - other people
have asked me the same question recetly)