25 Jan
2018
25 Jan
'18
12:31 p.m.
Andy Latto writes:
On Thu, Jan 25, 2018 at 1:08 AM, Keith F. Lynch <kfl@keithlynch.net> wrote:
"Keith F. Lynch" <kfl@KeithLynch.net> wrote:
Inspired by that, I tried searching for sets of positive integers such that the sums and differences of pairs of elements of the set weren't equal to elements of the set, and such that integer multiples of elements of the set weren't equal to elements of the set.
Eventually I found an infinite set with this property. Can anyone else find one? I'll post my solution in a week. . . . . . . . . . . . . . . . . . . . . . . The odd primes work.
Andy
Any integer multiple m >= 2 of the odd primes works. I.e. for any integer m >= 2, {m*p : p >= 3 and prime}. Tom