A002235 Numbers m such that 3*2^m - 1 is prime.
0, 1, 2, 3, 4, 6, 7, 11, 18, 34, 38, 43, 55, 64, 76, 94, 103, 143, 206, 216, 306, 324, 391, 458, 470, 827, 1274, 3276, 4204, 5134, 7559, 12676, 14898, 18123, 18819, 25690, 26459, 41628, 51387, 71783, 80330, 85687, 88171, 97063, 123630, 155930, 164987, 234760
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
- Jeppe Stig Nielsen, Table of n, a(n) for n = 1..68
- C. K. Caldwell, The Prime Pages: Database Search Output
- Wilfrid Keller, List of primes k.2^n - 1 for k < 300
- Mersenne Forum, 321 Search
- H. Riesel, Lucasian criteria for the primality of N=h.2^n-1, Math. Comp., 23 (1969), 869-875.
- H. Riesel, Lucasian criteria for the primality of N=h.2^n-1, Math. Comp., 23 (1969), 869-875. [Annotated scanned copy]
- Eric Weisstein's World of Mathematics, Integer Sequence Primes
- Eric Weisstein's World of Mathematics, Thabit ibn Kurrah Prime
- Eric Weisstein's World of Mathematics, Thabit ibn Kurrah Rule
- Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime
Crossrefs
Programs
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Mathematica
lst={};Do[If[PrimeQ[3*2^n-1], Print[n];AppendTo[lst, n]], {n, 10^5}];lst (* Vladimir Joseph Stephan Orlovsky, Aug 21 2008 *) -
PARI
is(n)=ispseudoprime(3<
Charles R Greathouse IV, Aug 27 2014
Extensions
More terms from Eric W. Weisstein, Sep 29 2007
a(60) = 11484018 from The Prime Pages, from Pierre CAMI, Nov 25 2014
a(61)-a(62) from The Prime Pages, from Eric W. Weisstein, Nov 03 2015
Terms moved from Data to b-file, and more terms added to b-file, by Jeppe Stig Nielsen, Sep 07 2021