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 A059802 #40 Apr 10 2025 06:47:02 %S A059802 3,43,59,191,223,349,563,709,743,1663,5471,17707,19609,35449,36697, %T A059802 45259,91493,246497,265007,289937 %N A059802 Numbers k such that 5^k - 4^k is prime. %C A059802 Some of the larger terms may only correspond to probable primes. %C A059802 5^1663 - 4^1663, a 1163-digit number, has been certified prime with Primo. - _Rick L. Shepherd_, Nov 13 2002 %C A059802 4 more terms found by Predrag Minovic in 2004: 35449, 36697, 45259, 91493. Corresponding numbers of decimal digits are 24778, 25651, 31635, 63951. - _Alexander Adamchuk_, Dec 02 2006 %t A059802 Select[Range[1000], PrimeQ[5^# - 4^#] &] (* _Alonso del Arte_, Sep 09 2013 *) %o A059802 (PARI) forprime(p=2,1e5,if(ispseudoprime(5^p-4^p),print1(p", "))) \\ _Charles R Greathouse IV_, Jun 10 2011 %Y A059802 Cf. A005060. %Y A059802 Cf. A000043, A057468, A059801, A128335, etc. %K A059802 nonn,hard,more %O A059802 1,1 %A A059802 _Mike Oakes_, Feb 23 2001 %E A059802 New term 246497 found by Jean-Louis Charton in 2008 corresponding to a probable prime with 172295 digits - _Jean-Louis Charton_, Sep 02 2009 %E A059802 New term a(19) = 265007 found by _Jean-Louis Charton_, Feb 19 2013 %E A059802 a(20) = 289937 found by _Jean-Louis Charton_, Mar 15 2013