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 A198725 #42 May 12 2024 10:09:12
%S A198725 5,41,257,1553,15672832817,121871948002097,4387390128075569,
%T A198725 161656255492952812128627920091307258673,
%U A198725 34917751186477807419783630739722367873841
%N A198725 Primes of the form (6^n-11)/5.
%C A198725 These primes are also given by sum 6^k -1 with k>0 and are then companions of A165210 which corresponds also to sum 6^k +1 with k>0. (Be careful: there is a shifting between the k and the n values).
%C A198725 Corresponding exponents n are in A199165. - _Gilbert Mozzo_, Nov 05 2011
%e A198725 (6^4-11)/5=257, which is in the sequence because it is prime.
%t A198725 lst={}; Do[If[PrimeQ[(6^n-11)/5], Print[(6^n-11)/5]; AppendTo[lst, (6^n-11)/5]], {n, 10^6}];
%o A198725 (Magma) [(6^n-11)/5: n in [1..10^3] | IsPrime((6^n-11) div 5)];
%o A198725 (PARI) for(n=1,1e4,if(ispseudoprime(t=6^n\5-2),print1(t", "))) \\ _Charles R Greathouse IV_, Nov 01 2011
%Y A198725 Cf. A165210, A004062, A199165.
%K A198725 nonn
%O A198725 1,1
%A A198725 _Gilbert Mozzo_, Oct 29 2011