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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.

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.

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

Table of n, a(n) for n=1..25.

Ray Ballinger, Proth Search Page

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

CROSSREFS

For more terms see A032362.

Sequence in context: A104427 A192229 A233696 * A039022 A182402 A079251

Adjacent sequences:  A002260 A002261 A002262 * A002264 A002265 A002266

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(25) from Vincenzo Librandi, Sep 07 2012.

STATUS

approved

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Last modified October 1 23:55 EDT 2014. Contains 247527 sequences.