

A200819


Primes of the form (2^n  n)*2^n  1.


7




OFFSET

1,1


COMMENTS

The corresponding n are 2, 4, 5, 8, 77, 377, 4547, ... (see A200818).
The generalization of this sequence is possible with the primes of the form (b^n +k)*b^n +1.
For n = 377, a(6) contains 227 digits;
For n = 4547, a(7) contains 2738 digits;
For n = 8248, a(8) contains 4966 digits.


LINKS

Table of n, a(n) for n=1..5.
Henri Lifchitz, New forms of primes


EXAMPLE

191 is in the sequence because, for n = 4, a(2) = (2^4  4)*2^4  1 = 191.


MATHEMATICA

a={}; Do[p=(2^nn)*2^n1; If[PrimeQ[p], AppendTo[a, p]], {n, 10^3}]; Print[a]


CROSSREFS

Cf. A200816, A200817, A200818, A200821, A200822, A200823, A200832.
Sequence in context: A303292 A010332 A198258 * A232146 A264353 A024096
Adjacent sequences: A200816 A200817 A200818 * A200820 A200821 A200822


KEYWORD

nonn,hard


AUTHOR

Michel Lagneau, Nov 23 2011


EXTENSIONS

a(8) from L. Joris Perrenet, Mar 17 2020


STATUS

approved



