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A262971 Numbers n such that 4^n + 31 is prime. 1
2, 6, 18, 270, 422, 596, 6068, 42140, 64178, 158732 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The next terms are > 250000.

Contains exactly the halved even terms of A247952.

LINKS

Table of n, a(n) for n=1..10.

MATHEMATICA

Select[Range[0, 250000], PrimeQ[4^# + 31] &]

PROG

(MAGMA) [n: n in [0..700] | IsPrime(4^n+31)]; // Vincenzo Librandi, Oct 06 2015

(PARI) for(n=1, 1e3, if(isprime(4^n+31), print1(n", "))) \\ Altug Alkan, Oct 06 2015

CROSSREFS

Cf. A247952.

Cf. similar sequences of the type "Numbers n such that 4^n+k is prime" listed in A253772.

Sequence in context: A056743 A064535 A240643 * A253380 A128123 A227884

Adjacent sequences:  A262968 A262969 A262970 * A262972 A262973 A262974

KEYWORD

nonn,more

AUTHOR

Robert Price, Oct 05 2015

STATUS

approved

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Last modified June 22 23:15 EDT 2017. Contains 288633 sequences.