End of infinite sequence

[Maximilian Hasler]

"Of course" Max's reply is in principle the right method to code a
sequence that is "infinite into the negative direction".
However, personally I frown a bit upon the fundamentalness of that sequence.
Chosing the English language (orthography of which is "arbitrary" and
changing with time) and the "latin" alphabet (which is itself changing
in time),
deciding to concatenate letters of words like twenty-two (i.e.
discarding spaces and/or dashes, contrary to the written definition
which takes up 4 lines...), but putting 0 for an inter-word space
resp. comma, ...
there's so much arbitraryness in that definition...
In every existing encyclopedia, choices must be made and are made on
what to include, and what to omit....

M.H.

On 6/5/07, Max Alekseyev <maxale at gmail.com> wrote:
> On 6/5/07, Eric Angelini <Eric.Angelini at kntv.be> wrote:
> >
> > Hello Seq-fans,
> > this is the end of an infinite sequence (no start, infinite
> > amount of terms, but a precise end):
> >
> > ... 20,23,5,14,20,25,20,23,15,0,6,9,22,5.
> >
> > How could I enter such a sequence in the OEIS?
>
> Why not reverse the order and turn it into a regular sequence:
>
> 5, 22, 9, 6, 0, 15, 23, ...
>
> ?
>
> Max
>




>Possible duplicates:
>
>A075821 and A100991 (after adjusting for offset differences)
>http://www.research.att.com/~njas/sequences/?q=id:A075821|id:A100991
>

These are duplicates. The statement " Some absent entries in the sequence may appear for some large perfect powers." in the first sequence should be deleted as in the second sequence there is a proof that the first sequence is full: " Excludes numbers of 100 or more, those which are a multiple of 2 but not 4, and those which are a multiple of 5 but not 25."

These are cool duplicates. These sequences prove that Numbers equal to the final two digits of their 21st, 41st, 61st, etc. powers are all possible last two digits (leading zeros omitted) of perfect power.

Tanya


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