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 A272345 #7 Jun 13 2017 10:36:46 %S A272345 1,3,5,29,41,83,471,725,1277,10271,15069,97731 %N A272345 Numbers n such that 8^n-7^(n-1) is prime. %C A272345 a(13) > 10^5. %e A272345 5 is a member since 8^5 - 7^4 = 32768 - 2401 = 30367 which is a prime number. %t A272345 Select[Range[0, 100000], PrimeQ[8^# - 7^(# - 1)] &] %o A272345 (PARI) is(n)=ispseudoprime(8^n-7^(n-1)) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A272345 Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883, A271884. %K A272345 nonn,more %O A272345 1,2 %A A272345 _Robert Price_, Apr 26 2016