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 A128025 #20 Jul 29 2023 21:49:10 %S A128025 2,3,7,19,31,67,89,9227,43891,854149 %N A128025 Numbers k such that (8^k - 3^k)/5 is prime. %C A128025 All terms are primes. %C A128025 Verified the first 8 terms in sequence. Also, the next number in the sequence, if one exists is > 43691. - _Robert Price_, Mar 16 2010 %C A128025 a(10) > 10^5. - _Robert Price_, Jul 27 2011 %C A128025 a(11) > 10^6. - _Jon Grantham_, Jul 29 2023 %H A128025 Jon Grantham and Andrew Granville, <a href="https://arxiv.org/abs/2307.07894">Fibonacci primes, primes of the form 2^n-k and beyond</a>, arXiv:2307.07894 [math.NT], 2023. %t A128025 k=5; Select[ Prime[ Range[1,200] ], PrimeQ[ ((k+3)^# - 3^#)/k ]& ] %o A128025 (PARI) is(n)=isprime((8^n-3^n)/5) \\ _Charles R Greathouse IV_, Feb 17 2017 %Y A128025 Cf. A028491 = numbers n such that (3^n - 1)/2 is prime. Cf. A057468 = numbers n such that 3^n - 2^n is prime. Cf. A059801 = numbers n such that 4^n - 3^n is prime. Cf. A121877 = numbers n such that (5^n - 3^n)/2 is a prime. Cf. A128024, A128026, A128027, A128028, A128029, A128030, A128031, A128032. %K A128025 hard,more,nonn %O A128025 1,1 %A A128025 _Alexander Adamchuk_, Feb 11 2007 %E A128025 9227 from _Farideh Firoozbakht_, Apr 08 2007 %E A128025 a(9) from _Robert Price_, Jul 27 2011 %E A128025 a(10) from _Jon Grantham_, Jul 29 2023