A239920 - OEIS

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A239920

Integers n such that 2n^2+1, 2n^3+1 and 2n^4+1 are prime.

1, 6, 21, 30, 96, 297, 375, 621, 1359, 1704, 1749, 1761, 3696, 3849, 4467, 8025, 8646, 9834, 11352, 15630, 17397, 17949, 19575, 20274, 27087, 28452, 30504, 32154, 32307, 33666, 35670, 36240, 37785, 37962, 39927, 40617, 42987, 44250, 47559, 49335, 49599

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Zak Seidov, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[0, 50000], PrimeQ[2 #^2 + 1] && PrimeQ[2 #^3 + 1] && PrimeQ[2 #^4 + 1]&] (* Vincenzo Librandi, Mar 30 2014 *)

PROG

(PARI) s=[]; for(n=1, 100000, if(isprime(2*n^2+1) && isprime(2*n^3+1) && isprime(2*n^4+1), s=concat(s, n))); s \\ Colin Barker, Mar 29 2014

CROSSREFS

Subsequence of A239874. Cf. A089001, A168550.

Sequence in context: A287165 A280296 A325407 * A173622 A302868 A064440

Adjacent sequences: A239917 A239918 A239919 * A239921 A239922 A239923

KEYWORD

nonn

AUTHOR

Zak Seidov, Mar 29 2014

STATUS

approved