[seqfan] Q regarding comment in A000079 (Powers of 2)

Joerg Arndt arndt at jjj.de
Sun Jun 21 05:10:55 CEST 2009


This comment needs corrections and clarifications:

With a different offset, number of n-permutations (n>=0) of 3 objects:
u, v, z with repetition allowed, containing exactly zero (0) or free
u's. For example, a(3)=8 because we have vvv, vvz, vzv, vzz, zvv, zvz,
zzv, zzz.
 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 08 2008

Firstly, "With a different offset" seems wrong,
a(3)==8 in the example and indeed a(3)==8 in the seq.

Also: "containing exactly zero (0) or free"
free --> three?

Examples for n==4 or n==5 may be instructive.
 From what I see the comment seems to be just wrong.





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