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This is the "Cunningham chain of the second kind of length 2", here is the OEIS reference and here is the Wikipedia entry; record primes of this type are listed here, the currently largest known prime $p$ such that $2p-1$ is also prime is $p=129431439657 \cdot 2^{170172} + 1$. It is a (still open) conjecture that the number of primes of this type less than $N$ grows with bound as $1.32\, N/\log^2 N$, see Sieving for large twin primes and Cunningham chains of length 2 of the second kind (2012).

This is the "Cunningham chain of the second kind of length 2", here is the OEIS reference and here is the Wikipedia entry; record primes of this type are listed here, the currently largest known (52138 digits) prime $p$ such that $2p-1$ is also prime is $p=129431439657 \cdot 2^{170171} + 1$. It is a (still open) conjecture that the number of primes of this type less than $N$ grows with bound as $1.32\, N/\log^2 N$, see Sieving for large twin primes and Cunningham chains of length 2 of the second kind (2012).

This is the "Cunningham chain of the second kind of length 2", here is the OEIS reference and here is the Wikipedia entry; record primes of this type are listed here, the currently largest known prime $p$ such that $2p-1$ is also prime is $p=129431439657 \cdot 2^{170172} + 1$. It is conjectured that the number of primes of this type less than $N$ grows with bound as $1.32\, N/\log^2 N$, see Sieving for large twin primes and cunningham chains of length 2 of the second kind.

This is the "Cunningham chain of the second kind of length 2", here is the OEIS reference and here is the Wikipedia entry; record primes of this type are listed here, the currently largest known prime $p$ such that $2p-1$ is also prime is $p=129431439657 \cdot 2^{170172} + 1$. It is a (still open) conjecture that the number of primes of this type less than $N$ grows with bound as $1.32\, N/\log^2 N$, see Sieving for large twin primes and Cunningham chains of length 2 of the second kind (2012).

This is the "Cunningham chain of the second kind of length 2", here is the OEIS reference and here is the Wikipedia entry; record primes of this type are listed here, the currently largest known prime $p$ such that $2p-1$ is also prime is $p=129431439657 \cdot 2^{170172} + 1$. It is conjectured that the number of primes of this type less than $N$ grows with bound as $1.32\, N/\log^2 N$. A research article with many references is Sieving for large twin primes and cunningham chains of length 2 of the second kind.

This is the "Cunningham chain of the second kind of length 2", here is the OEIS reference and here is the Wikipedia entry; record primes of this type are listed here, the currently largest known prime $p$ such that $2p-1$ is also prime is $p=129431439657 \cdot 2^{170172} + 1$. It is conjectured that the number of primes of this type less than $N$ grows with bound as $1.32\, N/\log^2 N$, see Sieving for large twin primes and cunningham chains of length 2 of the second kind.