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A352630 First of two consecutive primes p,q such that either p+2*q and (2*p+q)/5 or (p+2*q)/5 and 2*p+q are primes.

%I A352630 #7 Mar 27 2022 17:31:09
%S A352630 7,11,17,19,101,109,227,229,277,349,521,743,769,839,937,983,1151,1373,
%T A352630 1427,1609,1721,1823,2039,2081,2267,2273,2843,3373,3433,3779,3821,
%U A352630 3847,3967,4217,4517,4583,5417,5531,5669,5779,6197,6577,6701,6761,6883,7537,7669,7727,8467,8609,8837,9173,9281
%N A352630 First of two consecutive primes p,q such that either p+2*q and (2*p+q)/5 or (p+2*q)/5 and 2*p+q are primes.
%H A352630 Robert Israel, <a href="/A352630/b352630.txt">Table of n, a(n) for n = 1..10000</a>
%e A352630 a(3) = 17 is a term because it is prime, the next prime is 19, and (17+2*19)/5 = 11 and 2*17+19 = 53 are prime.
%p A352630 R:= NULL: q:= 2:
%p A352630 while q < 10000 do
%p A352630   p:= q; q:= nextprime(p); s:= p+2*q; t:= 2*p+q;
%p A352630   if (s mod 5 = 0 and isprime(s/5) and isprime(t)) or (t mod 5 = 0 and isprime(s) and isprime(t/5)) then R:= R,p;
%p A352630   fi
%p A352630 od:
%p A352630 R;
%Y A352630 Cf. A181848.
%K A352630 nonn
%O A352630 1,1
%A A352630 _J. M. Bergot_ and _Robert Israel_, Mar 24 2022