# [seqfan] Re: more strangeness (A000079 "Powers of 2" and many others)

Joerg Arndt arndt at jjj.de
Thu Mar 11 14:26:02 CET 2010

```... no answer at all on this one.

Just edited approx 27 seqs, including
hopefully all with the keyword 'core'
and definitely all mentioned below
(will do more later).

I dearly hope that further submissions by this
gentleman are met with profound skepticism.

One thing struck me while editing:
there seems to be an inofficial contest
to produce the most awful code to compute
such seqs as '2n+1', '3n', 'n^2+1' etc.
(this is not by Vincenzo but mostly by
one other individual).

* Joerg Arndt <arndt at jjj.de> [Mar 04. 2010 14:51]:
> Dear Vincenzo,
> in seq A000079 you give:
>
>   Except for the first term, number n such that if A=(7/8)*n^4;
>   B=(7/16)*n^4; C=(17/16)*n^4; D=(5/4)*n^4; then A^3+B^3+C^3=D^3 [From
>   Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Sep 08 2009]
>
> This is just an obfuscated way of saying that
>   (7/8)^3 + (7/16)^3+ (17/16)^3 == (5/4)^3
>
> Further, the statement has nothing whatsover to do with the sequence
> at hand (plus the initial qualification is plain wrong).
>
> Kindly remove the comment including the corresponding example which
>
>   For n=2, A=14, B=7, C=17, D=20, and 14^3+7^3+17^3=20^3 [From
>   Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jun 25 2009]
>
>
>   librandi -author:librandi
>
> There seem to be more examples of relations that need
> to be removed, a quick glance suggests to firstly check:
> A000027
> A000290
> A005408 (see my last mail)
> A005843
> A000668 (!)
> A002378
> A004526 (!  a(n)=floor(n*[sqrt(5)-sqrt(3)]) wrong!)
> A000302
> A002145 (!)
> (and apparently many more, I just checked 2 of 255 pages)
>
>
> best regards,  jj
>
>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/

```