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 A128348 #21 Jun 11 2021 04:58:31
%S A128348 2,3,31,41,53,101,421,1259,4721,45259
%N A128348 Numbers k such that (12^k - 5^k)/7 is prime.
%C A128348 All terms are primes.
%C A128348 Primality of the primes formed by a(8) and a(9) were certified by Primo. - _Ray G. Opao_, Jul 01 2012
%C A128348 a(11) > 10^5. - _Robert Price_, Mar 02 2013
%t A128348 k=12; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
%o A128348 (PARI) is(n)=isprime((12^n-5^n)/7) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y A128348 Cf. A062572, A128344, A128345, A128346, A128347, A128349, A128350, A128351, A128352, A128353, A128354.
%Y A128348 Cf. A004061, A082182, A121877, A059802.
%Y A128348 Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128338, A128339, A128340, A128341, A128342.
%K A128348 hard,more,nonn
%O A128348 1,1
%A A128348 _Alexander Adamchuk_, Feb 27 2007
%E A128348 a(8) and a(9) from _Ray G. Opao_, Jul 01 2012
%E A128348 a(10) from _Robert Price_, Mar 02 2013