A007656 (was: Re: : new keyword: probation

[Ralf Stephan]

You wrote 
> Well, there are some, like A007656 (atomic numbers of elements) which not so contingent as others.  Contingent on the laws of physics, maybe .... 

But only in a universal sense of the word, as it depends on 
features of the creation of the universe because only the most
abundant of the stable isotopes is given. Also, the last entries
are not confirmed.

There are two bigh problems with the sequence.

One problem is the definition which is only detailed in the comments, 
and should read (after Bedassy):

"Mass number of the most abundant of the stable nuclids with atomic
 number equal to n. If there is no stable isotope, chose the one with
 the longest decay time."

You see the second problem, now that the definition is written out.
If we have two presumed stable isotopes of an element, A and B, and A
is chosen because it is more abundant. Now, as we had it with Bismutum
recently, a stable isotope turns out to have a really long decay time,
and A turns out to be so... then suddenly one of the value changes.

I find this highly arbitrary and typical of attempts trying to 
squeeze physical realities into discrete values. More correct would
have been to take the stablest nuclide per se, but for that, we simply
don't know enough.


ralf