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A200821 Numbers n such that (2^n + n)*2^n - 1 is prime. 7
1, 2, 34, 107, 1568, 1933, 3551, 6793 (list; graph; refs; listen; history; text; internal format)
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^n-1], AppendTo[lst, n]], {n, 10000}]; lst

PROG

(PARI) is(n)=ispseudoprime((2^n+n)<<n-1) \\ 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

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Last modified September 25 06:32 EDT 2020. Contains 337335 sequences. (Running on oeis4.)