A remarkable sequence (FWD)
David W. Wilson
wilson at cabletron.com
Fri May 28 16:32:26 CEST 1999
Antreas P. Hatzipolakis wrote:
> From: xpolakis at hol.gr (Antreas P. Hatzipolakis)
> Newsgroups: sci.math
> Subject: Re: A remarkable sequence
> Date: 26 May 1999 16:32:25 GMT
>
> In article <374AC3C2.73CE0B0A at virginia.edu>, "Charles H. Giffen"
> <chg4k at virginia.edu> wrote:
>
> > Here's a recursive definition of a remarkable sequence
> > a[0],a[1],a[2],... of positive integers:
> >
> > a[0] = 1
> >
> > a[2k+1] = a[k] for k = 0,1,2,...
> >
> > a[2k] = a[k-1] + a[k} for k = 1,2,3,...
> >
> > The first few terms of this sequence are:
> >
> > k 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
> > a[k] 1 1 2 1 3 2 3 1 4 3 5 2 5 3 4 1 5 4
> >
> > 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
> > 7 3 8 5 7 2 7 5 8 3 7 4 5 1 6 5 9 4 11 7
I prefer the prettier recurrence
a(0) = 0; a(2k) = a(k); a(2k+1) = a(k) + a(k+1)
which generates the same sequence prepended by 0.
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