TAKE YOUR TIME · HINTS WELCOME · NO LIVES TO LOSE
One prime. Two lights.
Build a prime q. If 2q + 1 is prime too, a new pair of lights joins your harbor.
Light a little harbor.
Choose ballast to build q, then launch it. There is no timer and nothing to lose.
YOUR NUMBER · q?
ITS PARTNER · 2q + 1?
A little experiment is waiting for you.
A peek inside the number notes
A safe prime is a prime p whose (p − 1) / 2 is also prime. For example, 11 and 23 make a pair: 23 = 2 × 11 + 1. The smaller prime is called a Sophie Germain prime. These little numbers are checked exactly by trial division.
MADE BY YOU
Your lights along the shore
Your first discovery will have a place here.
Six safe-prime pairs, six welcoming lights. Keep this harbor or open a new one.
Your discoveries stay here for next time.
Start a fresh harbor
Your current collection stays until you press Start fresh. Keep a copy first if you like.