A098857 Numbers k such that 4^k*(2^k - 1) - 1 is prime.
1, 2, 18, 40, 50, 60, 62, 2688, 2880, 23678, 35076
Offset: 1
Crossrefs
Cf. A098856 ((4^k)*(2^k - 1) + 1 is prime).
Programs
-
Magma
[k: k in [1..100] | IsPrime(4^k*(2^k-1)-1)]; // Jinyuan Wang, Mar 19 2020
-
PARI
is(n)=ispseudoprime(4^n*(2^n-1)-1) \\ Charles R Greathouse IV, Jun 13 2017
Extensions
a(10) from Ray G. Opao, Sep 19 2005
a(11) from Michael S. Branicky, Oct 04 2024
Comments