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%I #9 Apr 23 2014 17:29:07
%S 5,11,19,29,31,71,101,109,131,151,179,211,229,239,269,281,311,491,521,
%T 541,719,739,751,809,919,929,971,1051,1061,1129,1181,1291,1361,1439,
%U 1481,1621,1741,1811,1831,2111,2131,2221,2371,2389,2411,2521,2539,2549,2689,2791
%N Primes p such that 2p+9 and 9p+2 are both prime.
%C All of the numbers in this sequence, except a(1), are either 1 or 9 mod 10.
%H Harvey P. Dale, <a href="/A239732/b239732.txt">Table of n, a(n) for n = 1..1000</a>
%e 5 is prime, 2*5+9 = 19 is prime, and 9*5+2 = 47 is prime. Thus, 5 is a member of this sequence.
%t Select[Prime[Range[500]],And@@PrimeQ[{2#+9,9#+2}]&] (* _Harvey P. Dale_, Apr 23 2014 *)
%o (Python)
%o import sympy
%o from sympy import isprime
%o {print(n) for n in range(5000) if isprime(2*n+9) and isprime(9*n+2) and isprime(n)}
%o (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
%K nonn,easy
%O 1,1
%A _Derek Orr_, Mar 25 2014
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