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A002274
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Numbers k such that 57*2^k+1 is prime.
(Formerly M0822 N0313)
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2
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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
(list;
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listen;
history;
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internal format)
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OFFSET
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1,1
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REFERENCES
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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).
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LINKS
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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), 673-681.
Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime
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PROG
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(PARI) is(n)=ispseudoprime(57*2^n+1) \\ Charles R Greathouse IV, May 22 2017
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CROSSREFS
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Sequence in context: A206821 A323003 A051468 * A329783 A287675 A273944
Adjacent sequences: A002271 A002272 A002273 * A002275 A002276 A002277
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KEYWORD
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hard,nonn
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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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
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STATUS
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approved
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