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Old 2019-04-30, 18:01   #6
robert44444uk
 
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Jun 2003
Oxford, UK

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Quote:
Originally Posted by henryzz View Post
Finding sets of 6 twins within a range of 81 is easy.
The first is 2595051759329+c with c = 0 2 12 14 30 32 42 44 72 74 78 80
There are several more that are easy to find with polysieve. I am ignoring all other values of c so there could be more than 6 sets of twins assuming a range of 81 is not the minimum.

0 2 6 8 18 20 30 32 36 38 48 50 is possible. I strongly suspect this is minimal for 6 twins. It is only necessary to search 1451 mod 11#=2310 + c for this form.

1256522812841 = 11#*543949269+1451 + c; c= 0 2 6 8 18 20 30 32 36 38 48 50

No proof that this is optimal for 7 but it won't be far off:
11#*491403340492+1451 + c; c = 0 2 6 8 18 20 30 32 36 38 48 50 60 62

I have started a search for 0 2 6 8 18 20 30 32 36 38 48 50 60 62 78 80. I think this will take a while though. Can anyone prove this is optimal?
henryzz, this is great!
  • Where are you getting the sets of possible positions?
  • How do you derive the primorial and the offset?


Thank you ATH for the very clear explanation of the mods around quads.
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