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A201357 Numbers n such that (2^n + n + 1)*2^n - 1 is prime. 7
1, 13, 1468, 2701, 2959, 3735, 8686 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

13 is in the sequence because (2^13 + 13 + 1)*2^13 - 1 = 67223551 is prime.

MATHEMATICA

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

PROG

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

CROSSREFS

Cf. A201356, A201358, A201359, A201360, A201361, A201362, A201363.

Sequence in context: A197097 A064962 A242562 * A220551 A185073 A185193

Adjacent sequences:  A201354 A201355 A201356 * A201358 A201359 A201360

KEYWORD

nonn,hard

AUTHOR

Michel Lagneau, Nov 30 2011

STATUS

approved

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Last modified January 21 05:39 EST 2020. Contains 331104 sequences. (Running on oeis4.)