A070325 Numbers n such that n+1, n^2+1 and n^4+1 are primes.

1, 2, 4, 6, 16, 180, 210, 430, 466, 556, 690, 760, 936, 966, 1150, 1870, 2266, 2646, 2676, 3390, 3516, 3910, 4006, 4566, 4590, 4936, 5086, 6576, 6970, 8626, 9276, 9336, 10006, 13686, 15510, 17320, 17550, 17850, 18040, 18060, 18586, 18700, 19380

Offset: 1

Author

Benoit Cloitre, May 11 2002

Keywords

• easy
• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A070689. [Zak Seidov, Apr 09 2011]

Programs

Mathematica

Do[ If[ PrimeQ[n + 1] && PrimeQ[n^2 + 1] && PrimeQ[n^4 + 1], Print[n]], {n, 1, 20000}]
Select[Prime[Range[2200]]-1,And@@PrimeQ[{#^2+1,#^4+1}]&] (* Harvey P. Dale, Sep 24 2011 *)

PARI

for(n=1,33000,if(isprime(n^2+1)*isprime(n^4+1)*isprime(n+1)==1,print1(n,",")))