OFFSET
1,1
COMMENTS
All of the numbers in this sequence, except a(1), are either 1 or 9 mod 10.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
5 is prime, 2*5+9 = 19 is prime, and 9*5+2 = 47 is prime. Thus, 5 is a member of this sequence.
MATHEMATICA
Select[Prime[Range[500]], And@@PrimeQ[{2#+9, 9#+2}]&] (* Harvey P. Dale, Apr 23 2014 *)
PROG
(Python)
import sympy
from sympy import isprime
{print(n) for n in range(5000) if isprime(2*n+9) and isprime(9*n+2) and isprime(n)}
(PARI) s=[]; forprime(p=2, 3000, if(isprime(2*p+9) && isprime(9*p+2), s=concat(s, p))); s \\ Colin Barker, Mar 26 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Derek Orr, Mar 25 2014
STATUS
approved