A002256 Numbers k such that 9*2^k + 1 is prime. (Formerly M0751 N0283)

1, 2, 3, 6, 7, 11, 14, 17, 33, 42, 43, 63, 65, 67, 81, 134, 162, 206, 211, 366, 663, 782, 1305, 1411, 1494, 2297, 2826, 3230, 3354, 3417, 3690, 4842, 5802, 6937, 7967, 9431, 13903, 22603, 24422, 39186, 43963, 47003, 49902, 67943, 114854, 127003, 145247

Offset

1,2

References

H. Riesel, "Prime numbers and computer methods for factorization", Progress in Mathematics, Vol. 57, Birkhauser, 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

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..60

Ray Ballinger, Proth Search Page

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300

C. K. Caldwell, The Prime Pages

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

Wilfrid Keller, List of primes k.2^n - 1 for k < 300

R. M. Robinson, A report on primes of the form k.2^n+1 and on factors of Fermat numbers, Proc. Amer. Math. Soc., 9 (1958), 673-681.

Eric Weisstein's World of Mathematics, Proth Prime

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Mathematica

Select[Range[2019], PrimeQ[9*2^#+1]&] (* Metin Sariyar, Sep 21 2019 *)

Crossrefs

Cf. A050528.

Sequence in context: A171033 A269983 A323066 * A230584 A294176 A008765

Adjacent sequences: A002253 A002254 A002255 * A002257 A002258 A002259

Keyword

nonn

Author

N. J. A. Sloane

Extensions

a(48) from Arkadiusz Wesolowski, Oct 22 2011

Added more terms (from http://web.archive.org/web/20161028080239/http://www.prothsearch.net/riesel.html), Joerg Arndt, Apr 07 2013

Terms moved from Data to b-file, and more terms put in b-file, by Jeppe Stig Nielsen, Sep 21 2019

Status

approved