[seqfan] Re: First fini sequence in the table?
Charles Greathouse
charles.greathouse at case.edu
Sun Dec 15 22:28:04 CET 2013
The Handbook was ordered by (what are now called) N-numbers, rather than
the A-numbers we use now. Likewise the Encyclopedia of Integer Sequences
was ordered by M-numbers. I don't know when the A-numbers (A for
"absolute") were first given, but between the time of the Handbook and the
Encyclopedia I think.
As to the reason for the initial ordering... Neil?
Charles Greathouse
Analyst/Programmer
Case Western Reserve University
On Sun, Dec 15, 2013 at 4:25 PM, <franktaw at netscape.net> wrote:
> Did A000053 and 54 replace something else, then? Or how did they get so
> early?
>
>
> Franklin T. Adams-Watters
>
> -----Original Message-----
> From: Neil Sloane <njasloane at gmail.com>
>
> I agree with Charles's list .
> However, as I remarked in the Preface to the 1973 book,
> some sequences were given the benefit of the doubt, like
> the sequence of Mersenne primes (which could still be a finite
> sequence as far as anyone knows).
> Neil
>
>
> On Sun, Dec 15, 2013 at 1:31 PM, Charles Greathouse <
> charles.greathouse at case.edu> wrote:
>
> It looks to me like the only finite sequences in the HIS were
>>
>> %N A000797 Numbers that are not the sum of 4 tetrahedral numbers.
>> %N A000926 Euler's "numerus idoneus" (idoneal, or suitable, or
>>
> convenient
>
>> numbers).
>> %N A001259 A sequence of sorted odd primes 3=p_1 < p_2 < ... < p_m
>>
> such
>
>> that p_i-2 divides the product p_1*p_2*...*p_(i-1) of the earlier
>>
> primes
>
>> and each prime factor of p_i-1 is a prime factor of twice the product.
>> %N A002205 The RAND Corporation list of a million random digits.
>> %N A003171 Discriminants of orders of imaginary quadratic fields with
>>
> 1
>
>> class per genus (a finite sequence).
>>
>> so that seems a 5-way tie for priority in 1973.
>>
>> Charles Greathouse
>> Analyst/Programmer
>> Case Western Reserve University
>>
>>
>> On Sun, Dec 15, 2013 at 12:55 PM, <franktaw at netscape.net> wrote:
>>
>> > By A-number, the first few fini sequences are A000053, A000054,
>>
> A000797,
>
>> > A000926, A001049, A001219, A001228, A001259, A001272, and A001293.
>> >
>> > On another issue, there are sequences such as A164081 that are
>>
> finite in
>
>> > the sense that from some point on they are zero. I think some such
>> > sequences are marked "fini", while others (like A164081) just have
>>
> lots
>
>> of
>> > zeros. We really ought to have a standard for this. (If we do decide
>> these
>> > should be marked finite, A000004 would of course be an exception.)
>> >
>> > Franklin T. Adams-Watters
>> >
>> >
>> > -----Original Message-----
>> > From: Alonso Del Arte <alonso.delarte at gmail.com>
>> > To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
>> > Sent: Sun, Dec 15, 2013 11:39 am
>> > Subject: [seqfan] First fini sequence in the table?
>> >
>> >
>> > As most of us know, for a long time Neil excluded finite sequences,
>> though
>> > he made exceptions for sequences not known to be infinite (e.g.,
>>
> Mersenne
>
>> > primes) and "for certain important number-theoretic sequences,such
>>
> as
>
>> > Euler's idoneal (or suitable) numbers."
>> >
>> > This raises the question: was A926 the first sequence in the OEIS
>>
> known
>
>> to
>> > be finite? At what point were the keywords fini and full accepted?
>> >
>> > Al
>> >
>> > --
>> > Alonso del Arte
>> > Author at SmashWords.com<https://www.smashwords.com/profile/view/
>> > AlonsoDelarte>
>> > Musician at ReverbNation.com
>>
> <http://www.reverbnation.com/alonsodelarte>
>
>> >
>> >
>> > _______________________________________________
>> >
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>> >
>>
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>>
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>
>
> --
> Dear Friends, I have now retired from AT&T. New coordinates:
>
> Neil J. A. Sloane, President, OEIS Foundation
> 11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
> Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
> Phone: 732 828 6098; home page: http://NeilSloane.com
> Email: njasloane at gmail.com
>
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