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 A082387 #30 Sep 08 2022 08:45:10
%S A082387 3,17,19,47,101,1709,2539,5591,6037,8011,19373,26489,27427
%N A082387 Numbers k such that (5^k + 2^k)/7 is prime.
%C A082387 Next term > 35000. - _Giovanni Resta_, Apr 06 2006
%C A082387 For (2^k + 5^k)/7 to be a prime, k must be a prime too. - _Alexander Adamchuk_, Feb 06 2007
%C A082387 No other terms less than 100000. - _Robert Price_, Apr 17 2012
%C A082387 Some of the results were computed using the PrimeFormGW (PFGW) primality-testing program. - _Hugo Pfoertner_, Nov 14 2019
%e A082387 a(1)=3 because (5^3 + 2^3)/7 = (125 + 8)/7 = 19 is prime.
%t A082387 Do[f=(2^n+5^n)/7; If[PrimeQ[f], Print[{n, f}]], {n, 1, 35000}] (* _Alexander Adamchuk_, Feb 06 2007 *)
%t A082387 Select[Range[0, 10000], PrimeQ[(5^# + 2^#)/7] &] (* _G. C. Greubel_, Nov 02 2018 *)
%o A082387 (PARI) is(n)=ispseudoprime((5^n + 2^n)/7) \\ _Charles R Greathouse IV_, Apr 28 2015
%o A082387 (Magma) [n : n in [1..10000] | IsPrime((5^n+2^n) div 7)]; // _G. C. Greubel_, Nov 02 2018
%Y A082387 Cf. A057469 ((2^k + 3^k)/5 is prime).
%K A082387 more,nonn
%O A082387 1,1
%A A082387 _Hugo Pfoertner_, May 22 2003
%E A082387 More terms from _Hugo Pfoertner_, Jun 23 2003
%E A082387 More terms from _Giovanni Resta_, Apr 06 2006