

A002256


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


4



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
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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. 381384.
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), 673681.
Eric Weisstein's World of Mathematics, Proth Prime
Index entries for sequences of n such that k*2^n1 (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 bfile, and more terms put in bfile, by Jeppe Stig Nielsen, Sep 21 2019


STATUS

approved



