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 A121248 #13 Jul 01 2024 02:42:12
%S A121248 0,1,2,6,9,10,32,36,55
%N A121248 Numbers k such that the sum of the first 2^k primes is a prime.
%C A121248 Corresponding primes in the sums of the first 2^n primes or primes in A099825[n] are given in A113617[n] = {2,5,17,8893,868151,3875933,219554912086470964379,...}.
%F A121248 A099825(a(n)) = A113617(n). - _Amiram Eldar_, Jul 01 2024
%t A121248 Do[f=Sum[Prime[k],{k,1,2^n}]; If[PrimeQ[f],Print[{n,f}]],{n,0,32}]
%Y A121248 Cf. A099825, A013916, A013918, A113617.
%K A121248 nonn,hard,more
%O A121248 1,3
%A A121248 _Alexander Adamchuk_, Aug 22 2006
%E A121248 Edited by _Robert G. Wilson v_, Aug 26 2006
%E A121248 a(7)-a(9) from _Amiram Eldar_, Jul 01 2024