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 A101406 #15 Jun 01 2019 09:36:40
%S A101406 3,2,3,2,2,3,3,19,2,2,45,7,15,7,5,5,44,2,4,3,84,62,128,5,4,90,16,37,
%T A101406 15,11,311,15,295,72,3,3,242,2,126,64,152,11,78,26,2,13,14,26,140,2,
%U A101406 24,16,157,4,49,13,2,123,64,16,61,206,6,76,412,31,84,23,24,9,471,26,422,227,8
%N A101406 a(n) = least k such that k^n*(k^n-1)-1 is prime.
%C A101406 Under the Bunyakovsky conjecture, a(n) exists for every n. [_Charles R Greathouse IV_, Dec 27 2011]
%H A101406 Pierre CAMI, <a href="/A101406/b101406.txt">Table of n, a(n) for n = 1..700</a>
%e A101406 2^5*(2^5-1) - 1 = 32*31 - 1 = 991 (prime) so for n=5 a(5)=2.
%t A101406 a = {}; Do[ k = 1; While[c = k^n; t = c*(c - 1) - 1; ! PrimeQ[t], k++ ]; AppendTo[a, k];, {n, 75}]; a (* _Ray Chandler_, Jan 27 2005 *)
%Y A101406 Cf. A101446.
%K A101406 nonn
%O A101406 1,1
%A A101406 _Pierre CAMI_, Jan 24 2005