A132190 Numbers n such that 7*n^2 + 1 is prime.
2, 4, 8, 10, 12, 14, 18, 20, 22, 26, 30, 34, 44, 46, 58, 66, 68, 70, 74, 76, 78, 84, 90, 96, 100, 106, 108, 110, 120, 128, 134, 140, 146, 152, 154, 156, 158, 162, 164, 168, 174, 184, 186, 188, 196, 200, 202, 210, 216, 228, 232, 238, 250, 252, 260, 262, 264, 268
Offset: 1
Examples
If n=2 then 7*n^2 + 1 = 29 (prime). If n=100 then 7*n^2 + 1 = 70001 (prime).
Crossrefs
Cf. A111051.
Programs
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Magma
[ n: n in [0..500] | IsPrime(7*n^2 + 1) ]; // Vincenzo Librandi, Jan 31 2011
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Mathematica
Select[Range[300], PrimeQ[7*#^2 + 1] &] (* Stefan Steinerberger, Jan 02 2008 *)
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PARI
is(n)=isprime(7*n^2+1) \\ Charles R Greathouse IV, Jun 13 2017
Extensions
More terms from Stefan Steinerberger, Jan 02 2008