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 A272781 #7 Jun 13 2017 14:42:11 %S A272781 9,14,32,48,78,85,108,134,834,1701,2275,3103,5795,10307,17243,24045, %T A272781 31085,32613,40014 %N A272781 Numbers n such that 6^n-5^(n+1) is prime. %C A272781 a(20) > 10^5. %e A272781 9 is a member since 6^9 - 5^10 = 10077696 - 9765625 = 312071 which is a prime number. %t A272781 Select[Range[0, 100000], PrimeQ[6^# - 5^(# + 1)] &] %o A272781 (PARI) is(n)=ispseudoprime(6^n-5^(n+1)) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A272781 Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883, A271884. %K A272781 nonn,more %O A272781 1,1 %A A272781 _Robert Price_, May 06 2016