

A201361


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


7



1, 2, 3, 8, 14, 35, 75, 83, 89, 90, 215, 342, 753, 1452, 4578
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..15.


EXAMPLE

3 is in the sequence because (2^3  3 + 1)*2^3  1 = 47 is prime.


MATHEMATICA

lst={}; Do[If[PrimeQ[(2^n  n+1)*2^n1], AppendTo[lst, n]], {n, 10000}]; lst


PROG

(PARI) is(n)=ispseudoprime((2^nn+1)<<n1) \\ Charles R Greathouse IV, Feb 17 2017


CROSSREFS

Cf. A201356, A201357, A201358, A201359, A201360, A201362, A201363.
Sequence in context: A171237 A173149 A128305 * A129700 A197466 A049344
Adjacent sequences: A201358 A201359 A201360 * A201362 A201363 A201364


KEYWORD

nonn,hard


AUTHOR

Michel Lagneau, Nov 30 2011


STATUS

approved



