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 A109080 #30 Mar 03 2021 09:37:20
%S A109080 1,2,14,26,50,126,144,260,624,1424,10472,19784,24558,797390
%N A109080 Numbers n such that 5^n - 2 is prime.
%C A109080 No more terms through 18000.
%C A109080 No more terms through 50000. - _Ryan Propper_, Dec 10 2008
%C A109080 a(14) > 10^5. - _Robert Price_, Feb 03 2014
%C A109080 a(14) > 185000. - _Tyler NeSmith_, Dec 13 2020
%C A109080 Searched 185000 to 800000. - _Paul Bourdelais_, Mar 03 2021
%H A109080 F. Firoozbakht, M. F. Hasler, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL13/Hasler/hasler2.html">Variations on Euclid's formula for Perfect Numbers</a>, JIS 13 (2010) #10.3.1
%e A109080 5^14 - 2 = 6103515623 is prime, hence 14 is in the sequence.
%t A109080 Do[If[PrimeQ[5^n - 2], Print[n]], {n, 1, 18000}]
%o A109080 (PARI) for(n=1, 10^5, if(ispseudoprime(5^n-2), print1(n, ", "))) \\ _Felix Fröhlich_, Jun 05 2014
%K A109080 hard,nonn
%O A109080 1,2
%A A109080 _Ryan Propper_, Jun 18 2005
%E A109080 Two more terms from _Ryan Propper_, Dec 10 2008
%E A109080 a(14) from _Paul Bourdelais_, Mar 03 2021