[seqfan] Re: More fractal triangles

[Reinhard Zumkeller]

see https://oeis.org/A249484

best, R.

2015-01-12 17:19 GMT+01:00 Eric Angelini <Eric.Angelini at kntv.be>:

> Hello SeqFans,
> Erase from S all pairs of integer [a(i), a(i+1)] having the
> same parity --like (2,4) or (3,5)-- and you'll get S back.
>
> S =
> 1,2,4,3,5,2,7,9,4,3,6,8,5,2,7,10,12,9,4,3,6,11,13,8,5,2,7,10,15,17,12,9,4,3,6,11,14,16,13,8,5,2,7,10,15,18,20,17,12,9,4,3,6,11,14,19,21,16,13,8,5,2,7,10,15,18,23,25,20,17,12,9,4,3,6,11,14,19,22,24,21,16,13,8,5,2,7,10,15,18,23,26,28,25,20,17,12,9,4,3,6,11,14,19,22,27,29,...
>
>
> The generating triangles [after a(1)=1] are:
>
> 1            2                                4,3
>            5,2,7                            9,4,3,6
>          8,5,2,7,10                      12,9,4,3,6,11
>       13,8,5,2,7,10,15                17,12,9,4,3,6,11,14
>    16,13,8,5,2,7,10,15,18          20,17,12,9,4,3,6,11,14,19
> 21,16,13,8,5,2,7,10,15,18,23    25,20,17,12,9,4,3,6,11,14,19,22
>             ...                               ...
>
> Read horizontally, line after line, to see S.
> Best,
> É.
>
>
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