Talk:Wagstaff primes: Difference between revisions
→3 divides all numbers of form 2n+1 when n is odd: Thanks to Nigel.
(3 divides all numbers of form 2<sup>n</sup>+1 when n is odd) |
(→3 divides all numbers of form 2n+1 when n is odd: Thanks to Nigel.) |
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n 1 2 3 4 5 6 7 8 9 ....
2<sup>n</sup>+1 will be divisible by 3 when when the [[Digital root]] of 2<sup>n</sup> is 2, 5, or 8 which from above corresponds to all odd values of n. Further for [[Wagstaff primes]] it can not be 8 because (2<sup>n</sup>+1)/3 will be divisible by 3.--[[User:Nigel Galloway|Nigel Galloway]] ([[User talk:Nigel Galloway|talk]]) 14:01, 15 September 2022 (UTC)
:Thanks for confirming that. I suspected it was the case but wasn't sure how to prove it. I've added a note to the task description and simplified my Wren solution a bit. --[[User:PureFox|PureFox]] ([[User talk:PureFox|talk]]) 16:27, 15 September 2022 (UTC)
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