[seqfan] Re: Rewriting squares
Kerry Mitchell
lkmitch at gmail.com
Sun May 12 15:52:26 CEST 2019
I've played a lot with these sequences and others like them (replace each
digit x with f(x)). A couple of my favorites are (because they have both
fixed leading and trailing sequences):
- Begin with 1 and replace each digit x with 15x. This sequence starts:
1, 15, 1575, 157510575, etc.
- Begin with 1 and replace each digit x with 16x: 1, 16, 1696,
169614496, etc.
- Begin with 3 and replace each digit x with 7^x: 3, 343, 3432401343,
etc.
Kerry
On Sun, May 12, 2019 at 2:13 AM Jeremy Gardiner via SeqFan <
seqfan at list.seqfan.eu> wrote:
> Beginning with a two-digit square, successively replace each digit with its
> square, then repeat.
>
> For example,
> 9
> 81
> 641
> 36161
> 9361361
> 8193619361
> 641819361819361
> 36161641819361641819361
> 93613613616164181936136161641819361
>
> The digits settle into a fixed sequence.
>
> Reading from the right we have (with leading 1 in the case of 7 and 9)
>
>
> 6,3,9,1,8,1,4,6,1,6,1,6,3,1,6,3,1,6,3,9,1,6,3,9,1,6,3,9,1,8,1,6,3,9,1,8,1,6,
> 3,9,1,8,1,4,6,1,6,3,9,1,8,1,4,6,1,6,3,9,1,8, ...
>
> or in the case of 25,
>
>
> 5,2,4,6,1,6,3,1,6,3,9,1,6,3,9,1,8,1,6,3,9,1,8,1,4,6,1,6,3,9,1,8,1,4,6,1,6,1,
> 6,3,1,6,3,9,1,8,1,4,6,1,6,1,6,3,1,6,3,1,6,3, ...
>
> Is this interesting, or too artificial for OEIS?
>
> Thanks,
> Jeremy Gardiner
>
>
>
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