# Is there an odd number which has no prime to prime matchings when compared with its reverse order? [closed] For example look at the number 9. It has prime-prime matching at 3,5, and 7.

For example the sequence of 13 has matchings at 1,3,7,11,13.

For example 15 has the matchings(crossings) at 3,5,11,13.

Is there an odd number for which the prime prime matchings do not occur?

• So you want $p+1$ to be the sum of two primes. Google for "Goldbach conjecture". – Wolfgang Dec 2 '15 at 8:48
• write natural numbers in order and then below them write those natural numbers in reverse order. and then match, intersect, or cross the primes in the two rows. if both rows has matching prime highlight it as done in the picture. – user42094 Dec 2 '15 at 8:54
• @wolfgang how is that linked with goldbach conjecture? – user42094 Dec 2 '15 at 8:56
• Have you looked at it? It conjectures there is no such odd number. So answering your question would be equivalent to solving it :) – Wolfgang Dec 2 '15 at 9:49
• There is a meta discussion related to this question: meta.mathoverflow.net/q/2627/55893 – Joonas Ilmavirta Dec 2 '15 at 14:11