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A181606 Twin primes ending in 9.

%I A181606 #13 May 21 2024 16:52:28
%S A181606 19,29,59,109,139,149,179,199,229,239,269,349,419,569,599,619,659,809,
%T A181606 829,859,1019,1049,1229,1279,1289,1319,1429,1489,1609,1619,1669,1699,
%U A181606 1789,1879,1949,1999,2029,2089,2129,2239,2269,2309,2339,2549,2659,2689
%N A181606 Twin primes ending in 9.
%H A181606 Robert Israel, <a href="/A181606/b181606.txt">Table of n, a(n) for n = 1..10000</a>
%H A181606 Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>
%p A181606 filter:= proc(n)
%p A181606   if not isprime(n) then return false fi;
%p A181606   if n mod 3 = 1 then isprime(n-2) else isprime(n+2) fi
%p A181606 end proc:
%p A181606 select(filter, [seq(i,i=9..10^4,10)]); # _Robert Israel_, Nov 19 2023
%t A181606 Select[Prime@ Range@ 800, Mod[ #, 10] == 9 && (PrimeQ[ # - 2] || PrimeQ[ # + 2]) &] (* _Robert G. Wilson v_, Nov 06 2010 *)
%t A181606 Select[Union[Flatten[Select[Partition[Prime[Range[400]],2,1],#[[2]]-#[[1]]==2&]]],Mod[#,10]==9&] (* _Harvey P. Dale_, May 21 2024 *)
%Y A181606 Cf. A001097, A181603, A181604, A181605.
%Y A181606 Union of A060229 and A282324.
%K A181606 nonn
%O A181606 1,1
%A A181606 _Omar E. Pol_, Nov 01 2010
%E A181606 More terms from _Robert G. Wilson v_, Nov 06 2010