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A253471 Numbers n such that 3^n + n^3 is prime. 2
2, 56, 10112, 63880, 78296, 125330, 222748 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms == 2 or 4 mod 6. - Robert Israel, Jan 01 2015

LINKS

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

EXAMPLE

2 is in the sequence because 3^2 + 2^3 = 17 is prime.

56 is in the sequence because 3^56 + 56^3 = 523347633027360537213687137 is prime.

MAPLE

select(t -> isprime(3^t+t^3), [seq(seq(6*i+j, j=[2, 4]), i=0..100)]); # Robert Israel, Jan 01 2015

MATHEMATICA

Do[If[PrimeQ[3^n+n^3], Print[n]], {n, 0, 12000}]

PROG

(PARI) is(n)=ispseudoprime(3^n+n^3) \\ Charles R Greathouse IV, Jun 06 2017

CROSSREFS

Cf. A001585 (3^n + n^3), A064539 (2^n + n^2 is prime), A094133 (Leyland primes).

Sequence in context: A206305 A325291 A326551 * A230879 A080318 A002542

Adjacent sequences:  A253468 A253469 A253470 * A253472 A253473 A253474

KEYWORD

nonn,hard,more

AUTHOR

Michel Lagneau, Jan 01 2015

EXTENSIONS

More terms from Hans Havermann, Apr 30 2015

STATUS

approved

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Last modified October 19 04:40 EDT 2019. Contains 328211 sequences. (Running on oeis4.)