25392RE: Re: [PrimeNumbers] Re: Yet another factoring puzzle
- Sep 27, 2013
---In firstname.lastname@example.org, <thefatphil@...> wrote:
> You only chose that target after
> the arrow had landed, I'm sure.
It happened thus:
1) I determined to factorize F(n)=((n^2-9)/4)^2-5 for
n <= 300, completely. As later shown in "factordb", I succeeded.
2) Meanwhile I ran OpenPFGW on n in [301,600], hoping for a
quick outlier and found none.
3) I estimated the probability of an easily discoverable
completely factorization for n>600 and found it to be small.
4) Recalling how I had once been caught out before by
a "probably no more" heuristic, I set a lone process running on
n in [601, 10000] so as not to be caught out again by Jens.
5) When I later looked and pfgw.log, it had found a hit at
So yes, Phil, you are quite correct that the puzzle was set
after this finding. However the heuristic that I gave was
made prior to my discovery, else I would not have said that
I was surprised.
The point that you are making (I think) is that I do such
expsriments often and only notice when the result is unexpected.
I don't tell folk about all the boring times when a negative
heuristic is borne out by a null result. That is the selection
David (guilty of not boring folk with what is routine)
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