A177105 Primes of the form 2*n^3-1.

53, 127, 431, 1999, 8191, 18521, 27647, 31249, 59581, 78607, 159013, 194671, 314927, 332749, 390223, 453961, 524287, 657017, 1062881, 1457999, 1507141, 1608713, 1940597, 2519423, 3455999, 4000751, 4393999, 5371237, 5606441

Offset: 1

Author

Vincenzo Librandi

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Programs

Magma

[a: n in [0..250] | IsPrime(a) where a is (2*n^3-1)];

Mathematica

Select[Table[2 n^3 - 1, {n, 0, 300}], PrimeQ] (* Vincenzo Librandi, Jul 25 2012 *)

PARI

for(n=0, 200, if(isprime(k=2*n^3-1), print1(k",  "))); \\ Vincenzo Librandi, Jul 25 2012

Formula

a(n) = 2*A214289(n)^3 -1. - R. J. Mathar, Aug 20 2019