VOOZH about

URL: https://oeis.org/A046847

⇱ A046847 - OEIS

login
A046847
Numbers k such that k*2^k - (k-1) is prime.
2
1, 2, 4, 6, 30, 32, 42, 120, 210, 248, 284, 574, 600, 628, 1600, 2800, 3396, 8892, 9426, 14630, 15444, 37384, 51062, 76364, 129566
OFFSET
1,2
COMMENTS
All terms > 1 are even. - Robert Israel, Sep 22 2014
MAPLE
select(t -> isprime(t*2^t - (t-1)), [$1..5000]); # Robert Israel, Sep 22 2014
PROG
(PARI) is(n)=ispseudoprime(n*2^n-(n-1)) \\ Charles R Greathouse IV, May 22 2017
CROSSREFS
Cf. A046846.
Sequence in context: A279419 A077633 A006933 * A339759 A121069 A100838
KEYWORD
nonn,hard,more
AUTHOR
EXTENSIONS
New name from Michel Marcus, Sep 22 2014
a(12)-a(17) from Robert Israel, Sep 22 2014
a(18)-a(23) from Michael S. Branicky, May 12 2023
a(24)-a(25) from Michael S. Branicky, Aug 18 2024
STATUS
approved