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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 (list; graph; refs; listen; history; text; internal format)
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.

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.

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^n-1 (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

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Last modified August 30 16:19 EDT 2014. Contains 246226 sequences.