[seqfan] Re: Another chemistry related sequence?
David Wilson
davidwwilson at comcast.net
Wed Sep 2 11:46:25 CEST 2009
a(43) = 0 as well.
I think "stable" once meant "will never spontaneously decay." The poster boy
for stability was the proton.
Wikipedia states that protons are now thought to have minimum half-life of
10^36 years, yet are still called stable.
I don't find a defined half-life cutoff point where unstable becomes stable,
maybe it's a matter of application.
----- Original Message -----
From: "Antti Karttunen" <antti.karttunen at gmail.com>
To: "Sequence Fanatics" <seqfan at list.seqfan.eu>
Sent: Wednesday, September 02, 2009 4:14 AM
Subject: [seqfan] Another chemistry related sequence?
> Here is an idea for atomic elements related sequence that should
> be reasonably well defined:
>
> a(n) = The number of stable isotopes the element number n has.
>
> If the information in Wikipedia is correct, the sequence should start as:
> 2,2,2,1,2,2,2,3,1,3,...
>
> Note that both a(83) ( http://en.wikipedia.org/wiki/Bismuth )
> and a(92) ( http://en.wikipedia.org/wiki/Uranium ) should be 0.
>
>
>
> (Or is it? Okay, we can speculate about the eventual decaying of protons,
> but... Also, I mean stable at "the normal room temperature conditions",
> not
> inside
> a particle accelerator.)
>
>
> Cheers,
>
> Antti.
>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/
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