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 A062572 #33 Jul 04 2021 07:52:25 %S A062572 2,5,11,13,23,61,83,421,1039,1511,31237,60413,113177,135647,258413 %N A062572 Numbers k such that 6^k - 5^k is prime. %C A062572 The 809- and 1176-digit numbers associated with the terms 1039 and 1511 have been certified prime with Primo. - _Rick L. Shepherd_, Nov 15 2002 %e A062572 2 is in the sequence because 6^2 - 5^2 = 36 - 25 = 11, which is prime. %e A062572 3 is not in the sequence because 6^3 - 5^3 = 216 - 125 = 91 = 7 * 13, which is not prime. %t A062572 Select[Range[1000], PrimeQ[6^# - 5^#] &] (* _Alonso del Arte_, Sep 04 2013 *) %o A062572 (PARI) forprime(p=2,1e4,if(ispseudoprime(6^n-5^n),print1(p", "))) \\ _Charles R Greathouse IV_, Jun 10 2011 %Y A062572 Cf. A000043, A057468, A059801, A059802, A062573-A062666. %K A062572 nonn,hard,more %O A062572 1,1 %A A062572 _Mike Oakes_, May 18 2001, May 19 2001 %E A062572 Edited by _T. D. Noe_, Oct 30 2008 %E A062572 Two more terms (31237 and 60413) found by Predrag Minovic in 2004 corresponding to probable primes with 24308 and 47011 digits. _Jean-Louis Charton_, Oct 06 2010 %E A062572 Two more terms (113177 and 135647) found by Jean-Louis Charton in 2009 corresponding to probable primes with 88069 and 105554 digits. _Jean-Louis Charton_, Oct 13 2010 %E A062572 a(15) from _Jean-Louis Charton_, Apr 08 2013