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A309328 Numbers n such that 2^n + n + 2 is prime. 1
0, 1, 3, 7, 9, 19, 27, 33, 147, 639, 12243 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

If it exists, a(12) > 30000.

LINKS

Table of n, a(n) for n=1..11.

MATHEMATICA

Select[Range[0, 2047], PrimeQ[2^# + # + 2] &] (* Alonso del Arte, Jul 23 2019 *)

PROG

(PARI) for(n=0, 15000, my(x=2^n+n+2); if(ispseudoprime(x), print1(n, ", ")))

CROSSREFS

A052968, A187733.

Sequence in context: A261072 A154508 A073573 * A059621 A034926 A224849

Adjacent sequences:  A309325 A309326 A309327 * A309329 A309330 A309331

KEYWORD

nonn,more,hard

AUTHOR

Hugo Pfoertner, Jul 23 2019

STATUS

approved

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Last modified June 19 23:27 EDT 2021. Contains 345154 sequences. (Running on oeis4.)