

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
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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^n1 (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 bfile, and more terms added to bfile, by Jeppe Stig Nielsen, Jan 19 2020


STATUS

approved



