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A070325 Numbers n such that n+1, n^2+1 and n^4+1 are primes. 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

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 *)

PROG

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

CROSSREFS

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

Sequence in context: A261864 A071243 A112086 * A199578 A076660 A046441

Adjacent sequences:  A070322 A070323 A070324 * A070326 A070327 A070328

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 11 2002

STATUS

approved

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Last modified March 30 04:55 EDT 2017. Contains 284296 sequences.