[seqfan] Re: A175388(?)

zak seidov zakseidov at yahoo.com
Sun Apr 25 11:10:51 CEST 2010


O,yes!

Sure it'd be 
a(n) <= A002275(a(n-1)),
thanks a lot!

Are you now OK with these two comments
(both mine!)?
(* Frankly, I'm not 100% sure that 
a(17) is OK. *)

Also, I'll add kw "base",
thanks!
Zak

--- On Sun, 4/25/10, Robert Munafo <mrob27 at gmail.com> wrote:

> From: Robert Munafo <mrob27 at gmail.com>
> Subject: [seqfan]  A175388(?)
> To: "Sequence Fanatics Discussion list" <seqfan at list.seqfan.eu>
> Date: Sunday, April 25, 2010, 12:59 AM
> I don't get the two comments, which
> seem to not only contradict each other
> but actually call attention to it: If a(n) <=
> A002275(n), then a(17) would
> have to be <= A002275(17) = (10^17-1)/9, but then the
> second comment clearly
> says a(17) >> 10^17.
> 
> I suggest that the writer of the first comment probably
> meant something like
> a(n) <= A002275(a(n-1)), because for all A002275(x), the
> sum of digits
> squared is x, and therefore a solution of length n can be
> made into a
> solution of length n+1 by prepending A002275(x) where x is
> the first item in
> the existing length n solution.
> 
> On Sat, Apr 24, 2010 at 23:43, zak seidov <zakseidov at yahoo.com>
> wrote:
> 
> > Not yet submitted -
> > pending for your comments/critics/praise;)
> >
> > Thanks, Zak
> >
> > %I A175388
> > %S A175388
> 1,2,11,23,19,7,29,16,5,8,9,3,36,6,88,269,15999
> > %N A175388 a(n) = smallest integer with exactly n
> iterations "summing  of
> > digits squared" ending with 1 or 4.
> > %C A175388 Sequence is infinite: for any n, a(n) <=
> R_n = A002275(n).
> > %C A175388 Actually, a(17) = 46*10^198 - 1, 45
> concatenated (or
> > concatenating?) with 197 nines.
> > %e A175388 a(0)=1 because 1 -> 1 (0 iterations)
> > %e A175388 a(1)=2 because 2 -> 4 (1 iteration)
> > %e A175388 a(2)=11 because 11 -> 2 -> 4 (2
> iterations)
> > %e A175388 a(3)=23 because 23 -> 13 -> 10 ->
> 1 (3 iterations)
> > %e A175388 a(4)=19 because 19 -> 82 -> 20 ->
> 4 (4 iterations).
> > %Y A175388 Cf. A002275, A176709.
> > %K A175388 nonn
> > %O A175388 0,2
> > %A A175388 Zak Seidov (zakseidov(AT)yahoo.com), Apr 24
> 2010
> >
> 
> -- 
>  Robert Munafo  --  mrob.com
> 
> _______________________________________________
> 
> Seqfan Mailing list - http://list.seqfan.eu/
>



      




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