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 A272272 #14 Mar 20 2022 04:26:26 %S A272272 4,8,24,36,48,246,608,734,774,824,948,1244,3230,4656,5448,6360,7598, %T A272272 15390,48158,86754 %N A272272 Numbers k such that 4^k-3^(k+1) is prime. %C A272272 a(21) > 10^5. %e A272272 8 is a member since 4^8 - 3^9 = 65536-19683 = 45853 which is a prime number. %t A272272 Select[Range[4, 100000], PrimeQ[4^# - 3^(# + 1)] &] %o A272272 (PARI) lista(nn) = for(n=1, nn, if(ispseudoprime(4^n-3^(n+1)), print1(n, ", "))); \\ _Altug Alkan_, Apr 24 2016 %Y A272272 Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883. %K A272272 nonn,more %O A272272 1,1 %A A272272 _Robert Price_, Apr 24 2016 %E A272272 Typo in a(11) corrected by _Georg Fischer_, Mar 19 2022