login
A002257
Numbers n such that 13*4^n + 1 is prime.
(Formerly M3247 N1310)
1
1, 4, 5, 10, 14, 41, 94, 154, 158, 500, 14140, 19004, 21928, 44009, 54629, 57148, 260653, 281228, 342280, 519448, 749938, 930866
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[2000], PrimeQ[13 4^#+1]&] (* Harvey P. Dale, Jan 22 2011 *)
PROG
(Magma) [ n: n in [1..800]|IsPrime(13*4^n+1)] // Vincenzo Librandi, Nov 21 2010
(PARI) for(n=1, 10^5, if(ispseudoprime(13*4^n+1), print1(n, ", "))); /* Joerg Arndt, Apr 07 2013 */
CROSSREFS
See A032356 (n such that 13*2^n+1 is prime) for more terms.
Sequence in context: A322468 A116930 A073119 * A101528 A119040 A287578
KEYWORD
nonn,more
EXTENSIONS
Added more terms (from A032356), Joerg Arndt, Apr 07 2013
STATUS
approved