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A050526 Primes of form 5*2^n+1. 9
11, 41, 641, 40961, 163841, 167772161, 2748779069441, 180143985094819841, 188894659314785808547841, 193428131138340667952988161, 850705917302346158658436518579420528641 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
All terms are odd since if n is even, then 5*2^n+1 is divisible by 3. - Michele Fabbrini, Jun 06 2021
LINKS
Ray Ballinger, Wilfried Keller, List of primes k*2^n + 1 for k < 300
Wikipedia, Proth's theorem
FORMULA
a(n) = A083575(A002254(n)). - Michel Marcus, Mar 29 2018
MAPLE
a:=(n, k)->`if`(isprime(k*2^n+1), k*2^n+1, NULL):
seq(a(n, 5), n=1..127); # Martin Renner, Mar 05 2018
PROG
(Magma) [a: n in [1..200] | IsPrime(a) where a is 5*2^n + 1]; // Vincenzo Librandi, Mar 06 2018
(GAP) Filtered(List([1..270], n->5*2^n + 1), IsPrime); # Muniru A Asiru, Mar 06 2018
(PARI) lista(nn) = {for(k=1, nn, if(ispseudoprime(p=5*2^k+1), print1(p, ", "))); } \\ Altug Alkan, Mar 29 2018
CROSSREFS
For the corresponding exponents n see A002254.
Sequence in context: A068840 A082424 A153173 * A257967 A104118 A159561
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 29 1999
STATUS
approved

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Last modified July 19 15:48 EDT 2024. Contains 374410 sequences. (Running on oeis4.)