[seqfan] Q regarding comment in A000079 (Powers of 2)
lajos66 at t-online.hu
lajos66 at t-online.hu
Mon Jun 29 11:13:16 CEST 2009
Hungary:
http://hu.wikipedia.org/wiki/Vari%C3%A1ci%C3%B3
* Az n db. elem k-ad osztályú variációinak száma
(jelölje V_n^k):
V_n^k = \frac{n!}{(n-k)!} = n(n-1)\ldots (n-k+1)
.
* Az n db. elem k-ad osztályú ismétléses variációinak
száma (jelölje V_n^{k,i}):
V_n^{k,i} = n^k
example, there :Two element
* aa
* ab
* ba
* bb
2^2= 4
example, there :Three (3) element
aaa, bbb, ccc, abc, acb, bac, bca, cab, cba, aab, aba,baa,
aac, aca, caa, abb, bab, bba, bbc, bcb, cbb. acc, cac, cca,
bcc, cbc, bcc. >>27
3^3= 27
4^4 = 64, etc...
Dátum: Wed, 24 Jun 2009 16:20:05 +1000
Feladó: Joerg Arndt <arndt at jjj.de>
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Tárgy: [seqfan] Re: Q regarding comment in A000079
(Powers of 2)
* Joerg Arndt <arndt at jjj.de> [Jun 24. 2009 15:54]:
> > [...]
Sloppy me, in
> Added this one:
> %C A000079 Permutations of n+1 elements where no element
is more
> than one position left of its original place. For
example, there
> are 4 such permutations of three elements: 123, 132,
213, and
> 312. The 8 such permutations of four elements are
1234, 1243,
> 1324, 1423, 2134, 2143, 3124, and 4123. [From Joerg
> Arndt (arndt(AT)jjj.de), June 24 2009]
>
it should be:
> than one position RIGHT of its original place. For
example, there
^^^^^
was: "left"
Dammit.
>
> >
> > Several other comments are not top quality either (or
are at least
> > obfuscating):
> > [...]
>
> I'd suggest to kill all of these, but leave it to someone
else.
>
I'll correct my mistake should it appear as submitted,
and also murder the "not top quality" comments you
mentioned.
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