[seqfan] Re: Help with A002793 needed/Karol A. Penson
maxale at gmail.com
Mon Jul 5 21:16:45 CEST 2010
The exponential generating function for A002793 is
( E_1(1) - E_1(1/(1-x)) ) * exp(1/(1-x)) / (1-x)
= ( Ei(-1/(1-x)) - Ei(-1) ) * exp(1/(1-x)) / (1-x)
where E_1(x) and Ei(x) are the exponential integrals
On Mon, Jul 5, 2010 at 1:02 PM, Karol PENSON <penson at lptl.jussieu.fr> wrote:
> Can anyone help with the following three questions concerning A002793:
> 1. is the formula for a(n) known ?
> 2. is any generating function (ogf , egf ... etc. ) of a(n) known ?
> 3. in one of my calculations the following splitting of a(n)'s
> appear :
> a(2)=4 =3+1
> a(3)=20 =11+8+1
> I would be happy to obtain the formula for the triangle.
> Thanks in advance , Karol A. Penson
> Seqfan Mailing list - http://list.seqfan.eu/
More information about the SeqFan