A239925 Integers n such that 2n^2+1, 2n^3+1, 2n^4+1 and 2n^5+1 are prime.

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

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 *)
Select[Range[179*10^4], AllTrue[2 #^Range[2, 5] + 1, PrimeQ] &] (* Harvey P. Dale, Sep 24 2021 *)

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: A358481 A300147 A087216 * A059049 A056071 A299410

Adjacent sequences: A239922 A239923 A239924 * A239926 A239927 A239928

Keyword

nonn

Author

Zak Seidov, Mar 29 2014

Status

approved