"A dream" of a series :-)

[Gottfried Helms]

Am 05.06.2008 15:54 schrieb Paul D Hanna:
> Gottfried (and Seqfans),
>      See the formula found in:
> A137852 
> G.f.: Product_{n>=1} (1 + a(n)*x^n/n!) = exp(x).
>  1, 1, -2, 9, -24, 130, -720, 8505, -35840, 412776, -3628800, 42030450,
> -479001600, ... 
> COMMENT 
> Equals signed A006973 (except for initial term), where A006973 lists the
> dimensions of representations by Witt vectors.
> 
> FORMULA 
> a(n) = (n-1)!*[(-1)^n + Sum_{d divides n, 1<d<n} d*( -a(d)/d! )^(n/d) ]
> for n>1 with a(1)=1.
>  
> Is that something like you were looking for?
>      Paul
Hi Paul -

 may be this formula is the most efficient one, I'll check it
 later. Thanks for the link!

 Kind regards -

 Gottfried



Max, Yasutoshi:

Yesterday I updated A137605 with Max's comment.
Is it ok now?