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2018-03-15, 12:12   #6
JeppeSN

"Jeppe"
Jan 2016
Denmark

25×5 Posts

Quote:
 Originally Posted by axn what is the form of factors for these numbers? It will be k*2^14+1, but will k itself has other restrictions (like k is a multiple of 2 or 4 or something? other modular restrictions?)
I would say the multiplier must be even, so it becomes (under a new convention where k is odd) $$k\cdot 2^n + 1$$ where $$n \ge 15$$. See also New GFN factors (Wilfrid Keller).

/JeppeSN