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A239925 Integers n such that 2n^2+1, 2n^3+1, 2n^4+1 and 2n^5+1 are prime. 3
1, 30, 8025, 44250, 49335, 49599, 155061, 218196, 255975, 293754, 324684, 333405, 336045, 367839, 381804, 416796, 476814, 514005, 529650, 558291, 668856, 682716, 747810, 893190, 930336, 933576, 1004004, 1246266, 1270860, 1383126, 1392111, 1427211, 1491645, 1497024, 1745904, 1786551 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..134

MATHEMATICA

Select[Range[0, 2000000], PrimeQ[2 #^2 + 1] && PrimeQ[2 #^3 + 1] && PrimeQ[2 #^4 + 1] && PrimeQ[2 #^5 + 1] &] (* Vincenzo Librandi, Mar 29 2014 *)

PROG

(PARI) s=[]; for(n=1, 2000000, if(isprime(2*n^2+1) && isprime(2*n^3+1) && isprime(2*n^4+1) && isprime(2*n^5+1), s=concat(s, n))); s \\ Colin Barker, Mar 29 2014

CROSSREFS

Subsequence of A239920. Cf. A089001, A168550, A239874.

Sequence in context: A184889 A300147 A087216 * A059049 A056071 A299410

Adjacent sequences:  A239922 A239923 A239924 * A239926 A239927 A239928

KEYWORD

nonn

AUTHOR

Zak Seidov, Mar 29 2014

STATUS

approved

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Last modified July 10 15:45 EDT 2020. Contains 335577 sequences. (Running on oeis4.)