[seqfan] Re: A family of quadratic recurrences

franktaw at netscape.net franktaw at netscape.net
Thu Oct 1 01:06:52 CEST 2009

A165896 should not, as I understand it, have the "frac" keyword.  This 
keyword means that there is some other sequence in the database, such 
that this sequence is the numerators and the other the denominators (or 
vice versa) of some sequence of fractions.

It does not mean that the sequence might contain non-integer values if 
extended.  If such values are found in the future, that would be the 
time to add the "frac" keyword and the sequence of denominators.

Franklin T. Adams-Watters

On Wed, Sep 30, 2009 at 1:31 PM, Jaume Oliver i Lafont
<joliverlafont at gmail.com> wrote:
> Hello Seqfans,
> In the family of quadratic recurrences defined by
> a(n)=sum(i=1,L-1,a(n-i)*sum(j=i,L-1,a(n-j)))/a(n-L), with L initial 
> I have not been able to find any noninteger value.
> Do these recurrences yield only integers? For any L>=2?
> This search is related to sequence
> http://research.att.com/~njas/sequences/A165896,
> which is the case L=4.
> Regards,
> Jaume

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