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 A367002 #25 Oct 29 2024 03:29:44
%S A367002 7,23,3,3,383,5,23,17,3,3,23,5,5,7,3,3,79,13,1879,13,3,3,47,7,229,5,3,
%T A367002 3,32212254719,263,223,5,3,3,5,73,17,1217,3,3,6709,29,7,71,3,3,11,97,
%U A367002 47,228713,3,3,5,37,5,7,3,3,9377,11,13,479,3,3,41,5,13,137
%N A367002 a(n) is the smallest prime factor of n*2^n-1.
%H A367002 Amiram Eldar, <a href="/A367002/b367002.txt">Table of n, a(n) for n = 2..884</a> (terms 2..325 from Robert Israel)
%F A367002 a(n) = A020639(A003261(n)).
%F A367002 a(n) = 3 iff n == 4 or 5 (mod 6). - _Robert Israel_, Nov 08 2023
%p A367002 f:= n -> min(numtheory:-factorset(n*2^n-1)):
%p A367002 map(f, [$2..100]); # _Robert Israel_, Nov 08 2023
%t A367002 Table[FactorInteger[n*2^n-1][[1,1]], {n,2,69}] (* _Paul F. Marrero Romero_, Dec 17 2023 *)
%Y A367002 Cf. A003261, A020639, A049479, A367003, A367004, A366899.
%K A367002 nonn
%O A367002 2,1
%A A367002 _Sean A. Irvine_, Oct 31 2023