This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A117847 #13 Sep 11 2021 10:47:47
%S A117847 1,2,3,4,8,9,10,15,24,35,37,79,340
%N A117847 Numbers k such that A060256(k)*prime(k)# - 1 is a Sophie Germain prime, where prime(k)# is the k-th primorial.
%C A117847 This sequence gives the firsts of twin primes (A060256(n)*prime(n)# - 1, A060256(n)*prime(n)# + 1) which are also Sophie Germain primes.
%C A117847 a(14) > 367. - _Amiram Eldar_, Sep 11 2021
%e A117847 16*(29#)-1 is the first of twin primes, 16 = A060256(10), 2*(16*(29#)-1)+1 is prime so 16*(29#)-1 is a Sophie Germain prime.
%t A117847 q[n_] := Module[{p = Product[Prime[i], {i,1,n}], k=1}, While[!PrimeQ[k*p-1] || !PrimeQ[k*p+1], k++]; PrimeQ[2*k*p - 1]]; Select[Range[100], q] (* _Amiram Eldar_, Sep 11 2021 *)
%Y A117847 Cf. A002110, A005384, A060256.
%K A117847 nonn,hard,more
%O A117847 1,2
%A A117847 _Pierre CAMI_, May 01 2006
%E A117847 a(1)-a(6) inserted by _Amiram Eldar_, Sep 11 2021