[seqfan] Re: D(n)

[Ami Eldar]

Hello David,

I am getting different terms, starting from the 4th term:
1, 11, 112, 166, 886, 4486, 22486, 112486, 166486, 488686, 4486486,...



On Sun, Dec 8, 2019 at 7:16 PM David Sycamore via SeqFan <
seqfan at list.seqfan.eu> wrote:

> Hello Seqfans,
> For n =d_1 d_2...d_k, define D(n) to be the unique number formed by adding
> all identical digits of n in order of appearance in n. (See draft A330273
> for details). Example D(224)=44 and D(44)=8.
>
> Let e(n) be the smallest number such that D*e(n)(n) can be reduced no
> further (then e(224)=2). If the digits of n are all distinct, then e(n)=0,
> since D(n)=n.
>
> Let a(n) be the smallest number k such that e(k)=n; (n>=0). Does a(n)
> always exist?
>
> I am trying to find some terms. So far I have candidates for a(n) up to
> n=7. (by hand) :
>
> 1, 11, 112, 1124, 11248, 122468, 2486, 122468..... ?
>
> But some of these may be wrong, I’m not sure....
>
> If anyone feels like computing the right numbers please have a go
> Thanks,
> David.
>
>
>
>
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