

A002256


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


2



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, 147073, 149143, 304607, 384990, 412034, 435743, 461081, 834810, 1051026, 1807574, 2543551
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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.
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.
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..58.
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
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


CROSSREFS

Cf. A050528.
Sequence in context: A056825 A056956 A171033 * A230584 A008765 A018468
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://www.prothsearch.net/riesel.html), Joerg Arndt, Apr 07 2013


STATUS

approved



