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 A014232 #31 Nov 09 2023 10:16:42
%S A014232 7,79,241,727,19681,31381059607,450283905890997361,
%T A014232 36472996377170786401,8727963568087712425891397479476727340041447,
%U A014232 4638397686588101979328150167890591454318967698007
%N A014232 Primes of the form 3^k - 2.
%D A014232 Daniel Minoli, Voice over MPLS, McGraw-Hill, New York, NY, 2002, ISBN 0-07-140615-8 (p.114-134) [From Daniel Minoli (daniel.minoli(AT)ses.com), Aug 26 2009]
%H A014232 Vincenzo Librandi, <a href="/A014232/b014232.txt">Table of n, a(n) for n = 1..20</a>
%H A014232 Daniel Minoli, W. Nakamine, <a href="http://dx.doi.org/10.1109/ICASSP.1980.1170906">Mersenne Numbers Rooted On 3 For Number Theoretic Transforms</a>, 1980 IEEE International Conf. on Acoust., Speech and Signal Processing. [From Daniel Minoli (daniel.minoli(AT)ses.com), Aug 26 2009]
%H A014232 Daniel Minoli, <a href="http://dx.doi.org/10.1090/S0025-5718-1980-0559206-9">Issues In Non-Linear Hyperperfect Numbers</a>, Mathematics of Computation, Vol. 34, No. 150, April 1980, pp. 639-645. [From Daniel Minoli (daniel.minoli(AT)ses.com), Aug 26 2009]
%F A014232 a(n) = 3^A014224(n) - 2. - _Elmo R. Oliveira_, Nov 09 2023
%t A014232 lst={};Do[p=3^n;If[PrimeQ[p-2],AppendTo[lst,p-2]],{n,2*5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, May 14 2010 *)
%t A014232 Select[3^Range[120]-2,PrimeQ] (* _Harvey P. Dale_, Aug 16 2011 *)
%o A014232 (Magma) [a: n in [1..200] | IsPrime(a) where a is 3^n-2]; // _Vincenzo Librandi_, Dec 07 2011
%o A014232 (PARI) for(n=2,1e3,if(ispseudoprime(t=3^n-2),print1(n", "))) \\ _Charles R Greathouse IV_, Dec 07 2011
%Y A014232 Cf. A000040, A007593, A014224 (corresponding k's).
%K A014232 nonn
%O A014232 1,1
%A A014232 _Jud McCranie_