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 A002235 Numbers m such that 3*2^m - 1 is prime. (Formerly M0545 N0195) 38
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 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..64 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 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 *) PROG (PARI) is(n)=ispseudoprime(3<

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Last modified December 1 20:47 EST 2023. Contains 367502 sequences. (Running on oeis4.)