A127845 - OEIS

%I #18 May 25 2023 16:20:18

%S 0,6,12,36,48,78,114,162,258,414,666,792,804,996,1044,1206,1308,1314,

%T 1356,1548,1584,1632,1734,1902,2106,2196,2214,2346,2358,2592,2634,

%U 2766,2808,2868,2892,2988,3072,3246,3432,3516,3576,3774,3894,3912,3996,4038

%N Numbers k such that k^2 + 5 and k^2 + 7 are twin primes.

%C All terms are multiples of 6. Intersection of A114270 and A078402.

%H Robert Israel, <a href="/A127845/b127845.txt">Table of n, a(n) for n = 1..7640</a>

%p filter:= n -> isprime(n^2+5) and isprime(n^2+7):

%p N:= 10000: # to get all entries <= 6*N

%p A127845:= select(filter, [6*n $ n=0..N]); # _Robert Israel_, Apr 17 2014

%t Select[Range[0,5000,6],AllTrue[#^2+{5,7},PrimeQ]&] (* _Harvey P. Dale_, May 25 2023 *)

%o (Magma) [n: n in [0..500] | IsPrime(n^2+5) and IsPrime(n^2+7)] // _Vincenzo Librandi_, Nov 23 2010

%Y Cf. A078402, A114270.

%K nonn

%O 1,2

%A _Zak Seidov_, Apr 05 2007