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 A199192 #9 May 28 2015 16:33:27
%S A199192 7,37,271,2269,19927,129159847,1162320517,
%T A199192 49269609804781974450852068861184694669,
%U A199192 589881151426658740854227725580736348850640632297373414091790995505756623268837
%N A199192 Primes of the form 3^(2n-3)+3^(n-1)+1.
%C A199192 The corresponding n are in A199191.
%C A199192 The next term -- a(10) -- has 152 digits. - _Harvey P. Dale_, May 28 2015
%F A199192 Primes in A198410.
%t A199192 a={}; Do[p=( (3^(n-1) + 1)^3 -1)/3^n; If[PrimeQ[p], AppendTo[a, p]], {n, 10^2}]; Print[a];
%t A199192 Select[Table[3^(2n-3)+3^(n-1)+1,{n,100}],PrimeQ] (* _Harvey P. Dale_, May 28 2015 *)
%Y A199192 Cf. A198410, A199191.
%K A199192 nonn
%O A199192 1,1
%A A199192 _Michel Lagneau_, Nov 03 2011