[seqfan] Re: Problem reproducing A019989, A019990, and A019991

[Marc LeBrun]

But, 2n=0 for n=0 ??
Sure, a(4) can be true, so A019989 can contain 2, but that's independent of a(0) -- the explicitly-stated boundary condition is that a(0) is true.  So why would 0 be omitted from the list?


And another thing: if the "b" and "c" defining relations are essentially identical (aka "symmetrical"), and they see the same initial values, how can those sequences ever diverge?
To break the symmetry perhaps some of those operations don't commute or associate and/or maybe they are computations done sequentially, instead of simultaneous relations?
(And, agreed, moreover there STILL needs to be a "1 --> 0" to keep things from saturating.)


I was hoping it was trying to be some kind of ternary Thue-Morse, or a counter of some color, but I don't immediately see how to reverse-engineer those from the current descriptions.
Hopefully the originators RWG & NJAS will fess up their intentions.


> On Apr 14, 2019, at 12:22 PM, Allan Wechsler <acwacw at gmail.com> wrote:
> 
> Oh, that part I understand! It's because a(0)=true, and A019989 is a list
> of all n such that a(2n)=true.
> 
> 
> On Sun, Apr 14, 2019 at 1:56 PM Marc LeBrun <mlb at well.com> wrote:
> 
>> For starters, why is it that A019989(0) is 2 and not 0?
>> 
>> 
>> --
>> Seqfan Mailing list - http://list.seqfan.eu/
>> 
> 
> --
> Seqfan Mailing list - http://list.seqfan.eu/