%I #18 May 23 2024 04:28:28
%S 7,23,47,167,263,359,383,479,503,719,839,863,887,983,1319,1367,1439,
%T 1487,1823,2039,2063,2207,2447,2879,2903,2999,3023,3119,3167,3623,
%U 3863,4007,4079,4127,4679,4703,4799,4919,5087,5399,5639,5807,5879,5927,6047
%N Safe primes of the form 8*k1: primes of the form 8*k1 such that 4*k1 is also a prime.
%H Harvey P. Dale, <a href="/A101789/b101789.txt">Table of n, a(n) for n = 1..10000</a>
%e 4*11 = 3 and 8*11 = 7 are primes, so the first term is 7.
%t Select[Prime[Range[800]],Mod[#,8]==7&&PrimeQ[(#1)/2]&] (* _Harvey P. Dale_, Jan 31 2012 *)
%o (PARI) is(k) = (k % 8 == 7) && isprime(k) && isprime(k\2); \\ _Amiram Eldar_, May 23 2024
%Y Intersection of A005385 and A007522.
%Y Cf. A002515.
%K easy,nonn
%O 1,1
%A Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004
