A032366 Numbers k such that 33*2^k+1 is prime.

1, 6, 13, 18, 21, 22, 25, 28, 66, 93, 118, 289, 412, 453, 525, 726, 828, 1420, 1630, 3076, 3118, 4452, 4941, 5236, 6346, 9133, 13401, 14214, 18766, 37249, 42685, 47805, 61372, 74178, 600270, 922782, 1130884, 2345001, 3176269, 3570132, 3649810

Offset

1,2

Comments

With a(37) = 1130884 the list is complete up to 2.1*10^6, but k = 2345001, 3176269 and 3570132 are also in the sequence, cf. Ballinger & Keller link. - M. F. Hasler, Jul 20 2019

The mentioned limit up to which the list is complete, has reached about 3.7*10^6 (PrimeGrid). - Jeppe Stig Nielsen, Sep 19 2019

Links

Table of n, a(n) for n=1..41.

Ray Ballinger, Proth Search Page

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300. (Created April 1998, updated July 2019.)

Chris K. Caldwell, The Prime Database: 33*2^3649810+1.

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

M. B. Porter et al, Factors of 33*2^n+1, OEIS wiki, updated July 2019

PrimeGrid, Fermat Divisor Search range statistics.

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

Prog

(PARI) is(n)=ispseudoprime(33*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A002240 (33*2^n-1 is prime).

Sequence in context: A197562 A322431 A153696 * A287237 A282975 A094696

Adjacent sequences: A032363 A032364 A032365 * A032367 A032368 A032369

Keyword

nonn,hard

Author

James R. Buddenhagen

Extensions

Added more terms from the Ballinger & Keller page. - Joerg Arndt, Apr 07 2013

Added & edited links & cross-references. - M. F. Hasler, Jul 20 2019

a(38)-a(41) from Jeppe Stig Nielsen, Sep 18 2019

Status

approved