A116954 Numbers k such that 3*k^3 + 1 is prime.
4, 10, 14, 16, 18, 20, 30, 36, 38, 48, 54, 58, 64, 70, 74, 86, 96, 106, 120, 140, 150, 154, 166, 170, 174, 176, 180, 200, 230, 234, 244, 260, 266, 268, 288, 296, 300, 304, 306, 308, 324, 330, 338, 340, 346, 348, 368, 384, 388, 394, 396, 406, 408, 434, 438, 440
Offset: 1
Examples
If k=48 then 3*k^3 + 1 = 331777 (prime).
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Crossrefs
Cf. A089001.
Programs
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Magma
[ n: n in [0..500] | IsPrime(3*n^3 + 1) ]; // Vincenzo Librandi, Jan 31 2011
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Maple
select(n -> isprime(3*n^3+1), [seq(i,i=2..1000,2)]); # Robert Israel, Jan 24 2018
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Mathematica
Select[Range[2000], PrimeQ[3#^3 + 1] &] (* Stefan Steinerberger, Apr 22 2006 *) Select[Range[2, 500], PrimeQ[3#^3 + 1] &] (* Stefan Steinerberger, Jul 22 2006 *)
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PARI
is(n)=isprime(3*n^3+1) \\ Charles R Greathouse IV, Feb 20 2017
Extensions
More terms from Stefan Steinerberger, Apr 22 2006, Jul 22 2006
Comments