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A049408 Numbers n such that n^4+n+1 is prime. 14
1, 2, 5, 6, 9, 11, 12, 14, 24, 26, 32, 36, 44, 47, 60, 69, 72, 74, 77, 89, 90, 102, 107, 119, 126, 131, 146, 147, 159, 162, 170, 171, 186, 191, 197, 204, 206, 219, 239, 240, 252, 266, 284, 285, 290, 296, 300, 324, 347, 351, 362, 384, 426, 437, 459, 465, 470 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For s = 5,8,11,14,17,20,..., n_s=1+n+n^s is always composite for any n>1. Also for n=1, n_s=3 is a prime for any s. Here we consider the case s=4.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

EXAMPLE

26 is OK because at s=4, n=26, n_s=1+n+n^s=457003 is a prime.

MATHEMATICA

Select[Range[1000], PrimeQ[1 + # + #^4] &] (* Vincenzo Librandi, Jul 28 2014 *)

PROG

(PARI) for(n=1, 1000, if(isprime(1+n+n^4), print1(n", ")))

(MAGMA) [n: n in [0..1000] | IsPrime(s) where s is 1+n+n^4]; // Vincenzo Librandi, Jul 28 2014

CROSSREFS

Cf. A002384, A075723, A049407.

Sequence in context: A281902 A153143 A075724 * A138970 A168550 A244737

Adjacent sequences:  A049405 A049406 A049407 * A049409 A049410 A049411

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified February 18 21:20 EST 2020. Contains 332028 sequences. (Running on oeis4.)