A001773 Numbers k such that 13*2^k - 1 is prime.

3, 7, 23, 287, 291, 795, 2203, 5711, 7927, 9443, 10095, 19071, 29611, 34651, 51875, 55343, 77511, 166303, 233207

Offset: 1

Author

N. J. A. Sloane

Keywords

• hard
• nonn
• more

References

• H. Riesel, "Prime numbers and computer methods for factorization", Progress in Mathematics, Vol. 57, Birkhäuser, Boston, 1985, Chap. 4, see pp. 381-384.
• N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300
• Wilfrid Keller, List of primes k.2^n - 1 for k < 300
• H. C. Williams and C. R. Zarnke, A report on prime numbers of the forms M = (6a+1)*2^(2m-1)-1 and (6a-1)*2^(2m)-1, Math. Comp., 22 (1968), 420-422.
• Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Crossrefs

Cf. A032356 (13*2^k+1 is prime).

Programs

PARI

is(n)=ispseudoprime(13*2^n-1) \\ Charles R Greathouse IV, May 22 2017

Extensions

More terms from Hugo Pfoertner, Jun 23 2004