A175152 - OEIS

%I #7 Sep 08 2022 08:45:51

%S 18,42,60,78,120,132,192,210,270,288,300,372,378,402,480,498,522,570,

%T 648,678,690,822,840,858,888,948,990,1032,1050,1140,1182,1218,1302,

%U 1308,1422,1452,1512,1530,1548,1572,1590,1740,1770,1938,1968,2010,2052,2058

%N Numbers n such that 11n-1 and 11n+1 are twin primes.

%H Vincenzo Librandi, <a href="/A175152/b175152.txt">Table of n, a(n) for n = 1..1000</a>

%e For n=18, 11*18-1=197 and 11*18+1=199

%t Select[Range[3000], PrimeQ[11 # - 1]&& PrimeQ[11 # + 1]&] (* _Vincenzo Librandi_, Apr 05 2013 *)

%o (Magma) [n: n in [1..3000] | IsPrime(11*n+1) and IsPrime(11*n-1)]

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Mar 08 2010