OFFSET
1,1
COMMENTS
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
MAPLE
select(t -> isprime(t) and isprime(t+2) and isprime(2*t+1), [3, seq(t, t=5..10000, 6)]); # Robert Israel, Feb 28 2017
MATHEMATICA
Select[Prime[Range[1000]], PrimeQ[#+2] && PrimeQ[2#+1]&] (* Vladimir Joseph Stephan Orlovsky, Mar 30 2011*)
PROG
(Magma) [p: p in PrimesUpTo(6200) | IsPrime(p+2) and IsPrime(2*p+1)]; // Vincenzo Librandi, Apr 08 2013
(PARI) is(n)=isprime(n) && isprime(n+2) && isprime(2*n+1) \\ Charles R Greathouse IV, Feb 25 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Corrected by Jud McCranie, Dec 30 2000
Name changed and incorrect comment and program removed by T. D. Noe, Aug 05 2010
STATUS
approved