[pavel_lishin]

Are there chains of Sophie Germain primes?

e.g.,

    p is prime
    2p + 1 is prime
    2(2p + 1) + 1 is prime...

[teraflop]

Wikipedia says these are called Cunningham chains: https://en.wikipedia.org/wiki/Cunningham_chain

There are no infinite chains, but there are conjectured to be inifinitely many finite chains of every possible length.