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 A147667 #26 Aug 03 2025 13:20:48
%S A147667 61,1136791005963704961126617632861,
%T A147667 173472015290681763212224222187425603741981,
%U A147667 31861838222649045530727106406255616308752331078816472270207782250106896363274089867800367051529351065966102374800998198276889145001421
%N A147667 Primes of the form 5^k - 4^k.
%C A147667 All terms are odd, and if k is even, then 5^k - 4^k is divisible by 3. [_Vincenzo Librandi_, Nov 25 2010]
%C A147667 The next term (a(5)) has 156 digits. - _Harvey P. Dale_, May 14 2022
%H A147667 Muniru A Asiru, <a href="/A147667/b147667.txt">Table of n, a(n) for n = 1..9</a>
%e A147667 5^3 - 4^3 = 125 - 64 = 61.
%p A147667 select(isprime, [seq(5^n - 4^n, n=0..200)]); # _Muniru A Asiru_, Mar 04 2018
%t A147667 lst={};Do[p=5^n-4^n;If[PrimeQ[p],AppendTo[lst,p]],{n,6!}];lst
%t A147667 Select[Table[5^n-4^n,{n,300}],PrimeQ] (* _Harvey P. Dale_, May 14 2022 *)
%o A147667 (GAP) Filtered(List([1..200],n->5^n - 4^n),IsPrime); # _Muniru A Asiru_, Mar 04 2018
%Y A147667 Cf. A059802 (corresponding n).
%K A147667 nonn
%O A147667 1,1
%A A147667 _Vladimir Joseph Stephan Orlovsky_, Nov 10 2008