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A002237 Numbers k such that 15*2^k - 1 is prime.

%I A002237 M0976 N0365 #45 Feb 12 2021 17:46:42
%S A002237 1,2,4,5,10,14,17,31,41,73,80,82,116,125,145,157,172,202,224,266,289,
%T A002237 293,463,1004,1246,2066,2431,2705,4622,5270,7613,21727,21962,40742,
%U A002237 41054,60622,83263,83669,91457,103940,104177,108124,115327,161453,172714,454681,568780,656264,712294,902474,1084010,1344313
%N A002237 Numbers k such that 15*2^k - 1 is prime.
%C A002237 The results were partially computed using the PrimeFormGW (PFGW) primality-testing program. - _Hugo Pfoertner_, Nov 14 2019
%D A002237 H. Riesel, "Prime numbers and computer methods for factorization", Progress in Mathematics, Vol. 57, Birkhauser, Boston, 1985, Chap. 4, see pp. 381-384.
%D A002237 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A002237 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A002237 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 A002237 Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k.2^n - 1 for k < 300</a>
%H A002237 Kosmaj, <a href="http://www.15k.org/riesellist.html">Riesel list k<300</a>. <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>
%H A002237 H. Riesel, <a href="http://dx.doi.org/10.1090/S0025-5718-1969-0262163-1">Lucasian criteria for the primality of N=h.2^n-1</a>, Math. Comp., 23 (1969), 869-875.
%H A002237 <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 A002237 (PARI) for(n=1, 10^10, if(ispseudoprime(15<<n-1), print1(n,", "))); \\ _Joerg Arndt_, Feb 23 2014
%Y A002237 Cf. A002258: 15*2^n+1 is prime.
%K A002237 hard,nonn
%O A002237 1,2
%A A002237 _N. J. A. Sloane_, _Simon Plouffe_
%E A002237 More terms from _Hugo Pfoertner_, Jun 29 2004
%E A002237 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008