OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MAPLE
a := proc (n) if isprime(n) = true and isprime(n^2+13*n+23) = true then n else end if end proc: seq(a(n), n = 2 .. 1300); # Emeric Deutsch, Jan 20 2009
MATHEMATICA
Select[Prime[Range[200]], PrimeQ[#^2 + 13 # + 23] &] (* Vincenzo Librandi, Aug 30 2012 *)
PROG
(Magma) [p: p in PrimesUpTo(1500) | IsPrime(p^2+13*p+23)] // Vincenzo Librandi, Aug 30 2012
(PARI) isok(p) = isprime(p) && isprime(p^2+13*p+23); \\ Michel Marcus, Feb 10 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jan 03 2009
EXTENSIONS
Extended by Emeric Deutsch, Jan 20 2009
STATUS
approved