cp's OEIS Frontend

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

%I A245640 #21 Sep 08 2022 08:46:09
%S A245640 2,3,5,7,13,17,43,61,67,73,97,127,131,137,167,241,281,307,353,433,463,
%T A245640 467,541,557,631,641,647,653,661,673,683,821,853,857,907,911,991,1033,
%U A245640 1063,1103,1117,1123,1291,1307,1433,1453,1511,1523,1553,1567,1571,1597,1601,1607
%N A245640 Prime numbers P such that 24*P^3-1 is also prime.
%H A245640 Pierre CAMI, <a href="/A245640/b245640.txt">Table of n, a(n) for n = 1..10000</a>
%e A245640 24*2^3-1=191 prime so a(1)=2.
%e A245640 24*3^3-1=647 prime so a(2)=3.
%t A245640 Select[Prime[Range[300]], PrimeQ[24 #^3 - 1] &] (* _Vincenzo Librandi_, Sep 07 2014 *)
%o A245640 (PFGW & SCRIPT)
%o A245640 SCRIPT
%o A245640 DIM n,0
%o A245640 DIMS t
%o A245640 OPENFILEOUT myf,a(n).txt
%o A245640 LABEL loop1
%o A245640 SET n,n+1
%o A245640 SETS t,%d,%d\,;n;p(n)
%o A245640 PRP 24*p(n)^3-1,t
%o A245640 IF ISPRP THEN GOTO a
%o A245640 GOTO loop1
%o A245640 LABEL a
%o A245640 WRITE myf,t
%o A245640 GOTO loop1
%o A245640 (PARI) select(p->isprime(24*p^3-1), primes(300)) \\ _Colin Barker_, Jul 28 2014
%o A245640 (Magma) [p: p in PrimesUpTo(1700)| IsPrime(24*p^3-1)]; // _Vincenzo Librandi_, Sep 07 2014
%Y A245640 Cf. A245639, A245641.
%K A245640 nonn,easy
%O A245640 1,1
%A A245640 _Pierre CAMI_, Jul 28 2014