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 A002263 Numbers n such that 25*4^n + 1 is prime. (Formerly M0721 N0269) 0
 1, 2, 3, 5, 10, 11, 26, 32, 39, 92, 116, 134, 170, 224, 277, 332, 370, 374, 640, 664, 820, 1657, 1952, 1969, 2576 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 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 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. MATHEMATICA Select[Range[0, 4000], PrimeQ[(25 4^# + 1)] &] (* Vincenzo Librandi, Sep 07 2012 *) PROG (MAGMA) [n: n in [0..3000] | IsPrime(25*4^n + 1)]; // Vincenzo Librandi, Sep 07 2012 (PARI) is(n)=ispseudoprime(25*4^n+1) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS For more terms see A032362. Sequence in context: A259732 A192229 A233696 * A249991 A039022 A182402 Adjacent sequences:  A002260 A002261 A002262 * A002264 A002265 A002266 KEYWORD nonn AUTHOR EXTENSIONS a(25) from Vincenzo Librandi, Sep 07 2012 STATUS approved

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Last modified April 8 08:54 EDT 2020. Contains 333313 sequences. (Running on oeis4.)