Timeline for Mapping from prime pairs to non prime pairs

5 events

when toggle format	what		by	license	comment
Dec 22, 2020 at 7:20	review	Close votes
Dec 22, 2020 at 15:17
Dec 22, 2020 at 6:16	vote	accept	Pruthviraj
Dec 22, 2020 at 3:42	answer	added	Alapan Das		timeline score: 1
Dec 21, 2020 at 19:12	comment	added	John Omielan		If $p = 3$, then $q \equiv 2 \pmod{3}$, so $p' = 23 \equiv 2 \pmod{3}$ and $q' \equiv 0 \pmod{3}$. If $p \equiv 1 \pmod{3}$, then $q \equiv 0 \pmod{3}$ and $q \gt 3$, so it can't be prime. Finally, with $p = 2$, then $q$ is not prime, but if otherwise $p \equiv 2 \pmod{3}$, then $q \equiv 1 \pmod{3}$, so $p' \equiv 2 \pmod{3}$ and $q' \equiv 0 \pmod{3}$. Thus, your statement is always true. In questions like this, you should always first check the smaller modulo values.
Dec 21, 2020 at 15:03	history	asked	Pruthviraj	CC BY-SA 4.0