A245640 Prime numbers P such that 24*P^3-1 is also prime.

2, 3, 5, 7, 13, 17, 43, 61, 67, 73, 97, 127, 131, 137, 167, 241, 281, 307, 353, 433, 463, 467, 541, 557, 631, 641, 647, 653, 661, 673, 683, 821, 853, 857, 907, 911, 991, 1033, 1063, 1103, 1117, 1123, 1291, 1307, 1433, 1453, 1511, 1523, 1553, 1567, 1571, 1597, 1601, 1607

Offset: 1

Author

Pierre CAMI, Jul 28 2014

Keywords

• nonn
• easy

Examples

			24*2^3-1=191 prime so a(1)=2.
24*3^3-1=647 prime so a(2)=3.
		

Links

• Pierre CAMI, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A245639, A245641.

Programs

Magma

[p: p in PrimesUpTo(1700)| IsPrime(24*p^3-1)]; // Vincenzo Librandi, Sep 07 2014

Mathematica

Select[Prime[Range[300]], PrimeQ[24 #^3 - 1] &] (* Vincenzo Librandi, Sep 07 2014 *)

PARI

select(p->isprime(24*p^3-1), primes(300)) \\ Colin Barker, Jul 28 2014