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

Next I'll try searching for an infinite set of integers such that no element can be generated by any arithmetic whatsoever on any of the other elements. Not even by something like (A-B)*(A-C)/(C+C+C+B^D). Is this a solved problem?

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