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 A124272 #16 Jul 13 2025 11:07:17
%S A124272 7,1469991559,2994181661163361882651
%N A124272 Primes in A124271, or primes of the form Sum_{i=1..k} (prime(i)^k - 1)/(prime(i) - 1).
%C A124272 The corresponding values of k are 2, 8, 14, ...
%C A124272 The next value of k is 667, so a(4) = 7.753...*10^2462. - _Amiram Eldar_, Jul 13 2025
%e A124272 7 is a term because A124271(2) = 7 is prime.
%t A124272 Do[f=Sum[(Prime[i]^n-1)/(Prime[i]-1),{i,1,n}];If[PrimeQ[f],Print[{n,f}]],{n,1,100}]
%Y A124272 Cf. A124271.
%K A124272 nonn,bref,hard
%O A124272 1,1
%A A124272 _Alexander Adamchuk_, Oct 23 2006