

A174821


Numbers n such that n^4  n^2  1 is prime.


0



2, 3, 4, 5, 6, 7, 11, 14, 17, 18, 19, 23, 25, 27, 32, 36, 41, 43, 54, 60, 65, 69, 72, 77, 80, 82, 83, 87, 88, 92, 93, 98, 110, 117, 121, 122, 126, 127, 135, 136, 138, 149, 150, 155, 157, 159, 168, 170, 172, 173, 176, 179, 183, 188, 198
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..55.


EXAMPLE

for n=2, a(2) = 3 and 3^4  3^2  1 = 71 is prime.


MATHEMATICA

lst={}; Do[If[PrimeQ[n^4n^21], AppendTo[lst, n]], {n, 400}]; lst


PROG

(PARI) is(n)=isprime(n^4n^21) \\ Charles R Greathouse IV, Jun 13 2017


CROSSREFS

Sequence in context: A192587 A174323 A103539 * A033086 A059768 A271835
Adjacent sequences: A174818 A174819 A174820 * A174822 A174823 A174824


KEYWORD

nonn,easy


AUTHOR

Michel Lagneau, Dec 01 2010


STATUS

approved



