login
Numbers n such that n^2-2 and (n+2)^2-2 are primes.
1

%I #9 May 24 2012 13:20:47

%S 3,5,7,13,19,27,33,35,47,61,69,75,117,119,231,237,257,265,299,301,313,

%T 335,355,357,441,447,467,489,495,523,573,607,713,761,943,993,1021,

%U 1069,1071,1141,1147,1175,1231,1239,1251,1265,1287,1357,1363,1365,1391,1461

%N Numbers n such that n^2-2 and (n+2)^2-2 are primes.

%C The number of such n's <= 10^n: 3, 12, 36, 216, 1279,... Cf A126334 for prime n's.

%H Harvey P. Dale, <a href="/A126108/b126108.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[10^5], PrimeQ[#^2-2] && PrimeQ[(#+2)^2-2]&]

%Y Cf. A126334.

%K nonn

%O 1,1

%A _Zak Seidov_, Mar 11 2007