[seqfan] Re: A120511 a(n) = min{j : A006949(j) = n}

Georgi Guninski guninski at guninski.com
Fri Sep 11 14:11:48 CEST 2009


On Fri, Sep 11, 2009 at 02:25:51AM -0400, Max Alekseyev wrote:
> On Tue, Sep 8, 2009 at 8:55 AM, Georgi Guninski <guninski at guninski.com> wrote:
> 
> >> A120511 a(n) = min{j : A006949(j) = n}
> >> A006949                A well-behaved cousin of the Hofstadter sequence
> >>
> >> seems to satisfy:
> 
> > a(n)=a(round(n/2)+(n mod 2))+n
> 
> I guess you meant a(n) = a(ceil(n/2)) + n.
>

thank you.

assuming A120511 is efficiently computable (your proof or the potential
doubling formulas i found) is A006949 efficiently computable by
something like a binary search in A120511?

-- 
georgi





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