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A002263 Numbers k such that 25*4^k + 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
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(25) from Vincenzo Librandi, Sep 07 2012
STATUS
approved

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Last modified March 28 14:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)