A002259 Numbers k such that 17*2^k + 1 is prime.
3, 15, 27, 51, 147, 243, 267, 347, 471, 747, 2163, 3087, 5355, 6539, 7311, 99231, 824451, 1388355, 1990299, 8636199
Offset: 1
References
- 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).
Links
- Ray Ballinger, Proth Search Page
- Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300
- 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
Programs
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PARI
is(n)=ispseudoprime(17*2^n+1) \\ Charles R Greathouse IV, Jun 06 2017
Extensions
Added more terms (from http://web.archive.org/web/20161028080239/http://www.prothsearch.net/riesel.html), Joerg Arndt, Apr 07 2013
a(20) from Jeppe Stig Nielsen, Dec 22 2024