A001773 Numbers k such that 13*2^k - 1 is prime. (Formerly M2686 N1076)

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

Offset

1,1

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

Table of n, a(n) for n=1..19.

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

Prog

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

Crossrefs

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

Sequence in context: A060235 A343815 A090188 * A067604 A090118 A099183

Adjacent sequences: A001770 A001771 A001772 * A001774 A001775 A001776

Keyword

hard,nonn,more

Author

N. J. A. Sloane

Extensions

More terms from Hugo Pfoertner, Jun 23 2004

Status

approved