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 A062608 #24 Jul 04 2021 08:21:43 %S A062608 2,3,5,47,67,103 %N A062608 Numbers k such that 42^k - 41^k is prime. %C A062608 Terms greater than 1000 are often only strong pseudoprimes. %C A062608 No further terms up to 5000. - _Harvey P. Dale_, Mar 13 2011 %C A062608 a(7) > 10^5. - _Robert Price_, Sep 21 2012 %t A062608 Select[Range[5000], PrimeQ[42^# - 41^#] &] (* _Harvey P. Dale_, Mar 13 2011 *) %o A062608 (PARI) is(n)=ispseudoprime(42^n-41^n) \\ _Charles R Greathouse IV_, Jun 12 2017 %Y A062608 Cf. A000043, A057468, A059801, A059802, A062572-A062666. %K A062608 nonn,hard,more %O A062608 1,1 %A A062608 _Mike Oakes_, May 18 2001, May 19 2001