

A002274


Numbers k such that 57*2^k+1 is prime.
(Formerly M0822 N0313)


2



2, 3, 7, 8, 10, 16, 18, 19, 40, 48, 55, 90, 96, 98, 190, 398, 456, 502, 719, 1312, 1399, 1828, 6723, 6816, 10680, 12592, 20742, 25010, 26838, 29623, 45435, 52783, 70950, 89691, 111691, 114400, 136152, 145183, 146223, 177459, 212908, 300910, 342151, 360447, 382156, 411635, 442948, 519862, 519892, 975036, 1158942, 1181438, 1756702, 2033643
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OFFSET

1,1


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

Table of n, a(n) for n=1..54.
Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300
Ray Ballinger, Proth Search Page
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.
Index entries for sequences of n such that k*2^n1 (or k*2^n+1) is prime


PROG

(PARI) is(n)=ispseudoprime(57*2^n+1) \\ Charles R Greathouse IV, May 22 2017


CROSSREFS

Sequence in context: A206821 A323003 A051468 * A329783 A287675 A273944
Adjacent sequences: A002271 A002272 A002273 * A002275 A002276 A002277


KEYWORD

hard,nonn


AUTHOR

N. J. A. Sloane.


EXTENSIONS

More terms from Hugo Pfoertner, Jun 20 2003
More terms (from http://web.archive.org/web/20161028080239/http://www.prothsearch.net/riesel.html), Joerg Arndt, Apr 07 2013
a(54) from http://www.prothsearch.com/riesel1.html by Robert Price, Dec 14 2018


STATUS

approved



