

A200821


Numbers n such that (2^n + n)*2^n  1 is prime.


7




OFFSET

1,2


COMMENTS

The generalization of this sequence is possible with the primes of the form (b^n +k)*b^n +1.


LINKS

Table of n, a(n) for n=1..8.
Henri Lifchitz, New forms of primes


EXAMPLE

2 is in the sequence because (2^2 + 2)*2^2  1 = 23 is prime.


MATHEMATICA

lst={}; Do[If[PrimeQ[(2^n + n)*2^n1], AppendTo[lst, n]], {n, 10000}]; lst


PROG

(PARI) is(n)=ispseudoprime((2^n+n)<<n1) \\ Charles R Greathouse IV, Feb 17 2017


CROSSREFS

Cf. A200816, A200817, A200818, A200819, A200822, A200823, A200832.
Sequence in context: A067130 A337397 A263226 * A200166 A226407 A226336
Adjacent sequences: A200818 A200819 A200820 * A200822 A200823 A200824


KEYWORD

nonn


AUTHOR

Michel Lagneau, Nov 23 2011


STATUS

approved



