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 A191548 #10 Feb 24 2020 08:09:12
%S A191548 31,5,3221,7,25646167,17,19,11,23,13,11831,5839,31,17,137,19,
%T A191548 751410597400064602523400427092397,661,127,23,47,46644217,101,79,2377,
%U A191548 29,7193,31,1310825268269643509279336731098526398390609803239319801398048897,97,755569
%N A191548 Smallest prime factor of prime(n)^n - 1 having the form k*n + 1.
%H A191548 Amiram Eldar, <a href="/A191548/b191548.txt">Table of n, a(n) for n = 3..96</a>
%e A191548 a(3) = 31 because prime(3)^3 - 1 = 5^3 - 1 = 124 = 2^2*31; the smallest prime divisor of the form k*n + 1 is 31 = 10*3 + 1 with k = 10.
%t A191548 Table[p = First /@ FactorInteger[Prime[n]^n - 1]; Select[p, Mod[#1, n] ==
%t A191548 1 &, 1][[1]], {n, 3, 30}]
%Y A191548 Cf. A069460 (greatest prime factor of prime(n)^n-1).
%K A191548 nonn
%O A191548 3,1
%A A191548 _Michel Lagneau_, Jun 05 2011