Investigating constant C=0.1688... in A081881 comment
David W. Cantrell
DWCantrell at sigmaxi.net
Sat Jan 26 03:26:36 CET 2008
Rainer Rosenthal wrote:
> David W. Cantrell wrote:
>
>>>>
>>>> a(n) = 1 + floor(C*exp(n)) (1)
>>>>
>>>> where
>>>>
>>>> C = 0.1688563566671442037316797755009010341... (2)
>
>> In <http://www.research.att.com/~njas/sequences/A081881>,
>> Benoit Cloitre had already said that "a(n) is asymptotic to
>> C*exp(n)
>> where C=0.1688...", which I suppose that has been proven. My simple
I should, rather, have said _simplistic_.
>> numerical investigation seemed to indicate that
>>
>> 0 < a(n) - C*exp(n) < 1. (3)
>>
>> I don't know if that's always true, but if it is, then of course
>> (1)
>> holds for all n.
>
> Based on your formula for A136617 we can do more such simple
> numerical
> investigations in a reasonable amount of time. I did so and I found
> that (3) doesn't hold for n = 165. I will demonstrate this now.
Many thanks for your investigations! I confirm your observation.
Best regards,
David
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