login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A032473 Numbers k such that 193*2^k+1 is prime. 1
2, 4, 8, 12, 24, 28, 30, 70, 82, 100, 124, 134, 434, 478, 540, 708, 952, 1052, 1070, 1528, 1804, 2568, 2914, 3712, 16582, 17342, 23368, 23942, 35998, 72174, 142022, 160658, 177768, 215140, 238092, 313540, 461470, 484500, 868328, 880188, 1679938, 1728894 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..45

Ray Ballinger, Proth Search Page

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300

Wilfrid Keller, List of primes k.2^n - 1 for k < 300

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

MAPLE

select(k->isprime(193*2^k+1), [$0..1000]); # Muniru A Asiru, Dec 18 2018

MATHEMATICA

Select[Range[1000], PrimeQ[193*2^# + 1] & ] (* Robert Price, Dec 18 2018 *)

PROG

(PARI) is(n)=ispseudoprime(193*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A103787 A327480 A330022 * A084422 A175841 A293601

Adjacent sequences:  A032470 A032471 A032472 * A032474 A032475 A032476

KEYWORD

nonn,hard

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(31)-a(43) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 18 2018

Term moved from Data section to b-file, and more terms added to b-file, by Jeppe Stig Nielsen, Jan 19 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 28 14:26 EST 2022. Contains 350656 sequences. (Running on oeis4.)