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

%I M0822 N0313 #41 Oct 15 2023 00:00:14

%S 2,3,7,8,10,16,18,19,40,48,55,90,96,98,190,398,456,502,719,1312,1399,

%T 1828,6723,6816,10680,12592,20742,25010,26838,29623,45435,52783,70950,

%U 89691,111691,114400,136152,145183,146223,177459,212908,300910,342151,360447,382156,411635,442948,519862,519892,975036,1158942,1181438,1756702,2033643

%N Numbers k such that 57*2^k + 1 is prime.

%D H. Riesel, "Prime numbers and computer methods for factorization", Progress in Mathematics, Vol. 57, Birkhauser, Boston, 1985, Chap. 4, see pp. 381-384.

%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Ray Ballinger and Wilfrid Keller, <a href="http://www.prothsearch.com/riesel1.html">List of primes k·2^n + 1 for k < 300</a>.

%H Ray Ballinger, <a href="http://www.prothsearch.com/index.html">Proth Search Page</a>.

%H Y. Gallot, <a href="http://www.utm.edu/research/primes/programs/gallot/index.html">Proth.exe: Windows Program for Finding Large Primes</a>.

%H Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k·2^n - 1 for k < 300</a>.

%H R. M. Robinson, <a href="https://doi.org/10.1090/S0002-9939-1958-0096614-7">A report on primes of the form k·2^n+1 and on factors of Fermat numbers</a>, Proc. Amer. Math. Soc., 9 (1958), 673-681.

%H <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime</a>

%o (PARI) is(n)=ispseudoprime(57*2^n+1) \\ _Charles R Greathouse IV_, May 22 2017

%K hard,nonn

%O 1,1

%A _N. J. A. Sloane_

%E More terms from _Hugo Pfoertner_, Jun 20 2003

%E More terms (from http://web.archive.org/web/20161028080239/http://www.prothsearch.net/riesel.html), _Joerg Arndt_, Apr 07 2013

%E a(54) from http://www.prothsearch.com/riesel1.html by _Robert Price_, Dec 14 2018