

A032365


Numbers k such that 31*2^k+1 is prime.


1



8, 60, 68, 140, 216, 416, 1808, 1944, 9096, 76596, 93168, 4673544, 5560820
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..13.
Ray Ballinger, Proth Search Page
Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300
Chris K. Caldwell, The Prime Database: 31*2^4673544 + 1
Chris K. Caldwell, The Prime Database: 31*2^5560820 + 1
Y. Gallot, Proth.exe: Windows Program for Finding Large Primes
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


PROG

(PARI) is(n)=ispseudoprime(31*2^n+1) \\ Charles R Greathouse IV, Jun 12 2017


CROSSREFS

Sequence in context: A186362 A285231 A264817 * A250315 A074423 A199906
Adjacent sequences: A032362 A032363 A032364 * A032366 A032367 A032368


KEYWORD

nonn,hard


AUTHOR

James R. Buddenhagen


EXTENSIONS

a(12) from Jeppe Stig Nielsen, Oct 14 2019
a(13) from Jeppe Stig Nielsen, Jan 29 2020


STATUS

approved



