# [seqfan] Re: More (and more) fractal trees - and erasures

Reinhard Zumkeller reinhard.zumkeller at gmail.com
Thu Jan 8 15:49:09 CET 2015

```https://oeis.org/draft/A253672

. . .   the name could be nicer

Best, R.

2015-01-08 14:47 GMT+01:00 Eric Angelini <Eric.Angelini at kntv.be>:

> Hello SeqFans,
>
> Consider this fractal tree: to recover S, you have to erase here all
> 3-consecutive integers chunks in S {that is [n(i),n(i+1),n(i+2)], for
> instance [0,1,2] or [3,4,5] or [6,7,8], etc.}
>
> S =
> 0,1,2,0,1,3,4,5,2,0,1,3,4,6,7,8,5,2,0,1,3,4,6,7,9,10,11,8,5,2,0,1,3,4,6,7,9,10,12,13,14,11,8,5,2,0,1,3,4,6,7,9,10,12,13,15,16,17,14,11,8,5,2,0,1,3,4,6,7,9,10,12,13,15,16,18,19,20,17,14,11,8,5,2,0,1,3,4,6,7,9,10,12,13,15,16,18,19,21,22,23,20,17,14,11,8,5,2,...
>
> The pattern is quite obvious - at each step you reproduce the previous
> one, inserting between n(i+1) and n(i+2) the next triplet [n(i+k),
> n(i+k+1), n(i+k+2)] :
>
>                                     [0,1,2],
>                                 0,1,[3,4,5],2,
>                             0,1,3,4,[6,7,8],5,2,
>                        0,1,3,4,6,7,[9,10,11],8,5,2,
>                   0,1,3,4,6,7,9,10,[12,13,14],11,8,5,2,
>             0,1,3,4,6,7,9,10,12,13,[15,16,17],14,11,8,5,2,
>       0,1,3,4,6,7,9,10,12,13,15,16,[18,19,20],17,14,11,8,5,2,
> 0,1,3,4,6,7,9,10,12,13,15,16,18,19,[21,22,23],20,17,14,11,8,5,2,...
>
> Best,
> É.
>
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>
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>
```