

A028823


Numbers n such that n^2 + n + 17 is prime.


4



0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 19, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 35, 37, 38, 40, 42, 44, 45, 46, 47, 49, 53, 56, 57, 59, 60, 62, 63, 64, 70, 72, 73, 75, 76, 79, 81, 82, 86, 87, 91, 92, 95, 98, 103, 104, 108, 109, 110, 113, 114
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OFFSET

1,3


COMMENTS

Complement of A007636.  Michel Marcus, Jun 17 2013


LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000
Patrick De Geest, Palindromic Quasi_Over_Squares of the form n^2+(n+X)


EXAMPLE

15^2 + 15 + 17 = 257, which is prime, so 15 is in the sequence.
16^2 + 16 + 17 = 289 = 17^2, so 16 is not in the sequence. Much more obviously, 17 is not in the sequence either.


MATHEMATICA

Select[Range[0, 199], PrimeQ[#^2 + # + 17] &] (* Indranil Ghosh, Mar 19 2017 *)


PROG

(MAGMA) [n: n in [0..1000] IsPrime(n^2+n+17)] // Vincenzo Librandi, Nov 19 2010
(PARI) is(n)=isprime(n^2+n+17) \\ Charles R Greathouse IV, Feb 20 2017
(Python)
from sympy import isprime
print [n for n in range(0, 201) if isprime(n**2 + n + 17)] # Indranil Ghosh, Mar 19 2017


CROSSREFS

Cf. A007635, A007636, A014556.
Sequence in context: A279487 A046039 A023784 * A258264 A074739 A246096
Adjacent sequences: A028820 A028821 A028822 * A028824 A028825 A028826


KEYWORD

nonn


AUTHOR

Patrick De Geest


STATUS

approved



