====== Lemoine's conjecture ====== In 1895, French mathematician Émile Lemoine proposed that : >2//n// + 1 = //p// + 2//q// always has a solution in primes //p// and //q// (not necessarily distinct) for //n// > 2. >\\ [source below] In plain language : >All odd integers greater than 5 can be represented as the sum of an odd prime number and an even semiprime.* see notes >\\ [source below] e.g. 13=3+(2×5)\\ 19=5+(2×7) Although the conjecture has been computationally checked up to at least 1010, there is currently no proof (or disproof). More info at [[https://en.wikipedia.org/wiki/Lemoine%27s_conjecture|Wikipedia]] //Notes:// [1] The conjecture is also called //Levy's Conjecture// which was (re)proposed in 1963. [2] An 'even semiprime' is any even number which is the product of two prime numbers multiplied together.