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 A094921 #15 Jan 13 2025 16:28:04
%S A094921 0,1,1,3,0,1,1,3,7,5,1,7,1,7,10,3,1,7,1,15,1,7,1,19,0,7,16,7,1,25,1,
%T A094921 19,10,7,15,7,1,7,4,35,1,7,1,39,25,7,1,19,29,25,43,51,1,43,15,35,43,7,
%U A094921 1,55,1,7,43,51,60,25,1,55,43,35,1,43,1,7,25,31,8,49,1,35,16,7,1,7,25,7,43,27
%N A094921 a(n) = (6^n-1)/5 mod n.
%H A094921 Antti Karttunen, <a href="/A094921/b094921.txt">Table of n, a(n) for n = 1..20000</a>
%t A094921 Table[Mod[(6^n-1)/5,n],{n,90}] (* _Harvey P. Dale_, Nov 25 2012 *)
%o A094921 (PARI) A094921(n) = (((6^n-1)/5)%n); \\ _Antti Karttunen_, Jan 13 2025
%Y A094921 Cf. A003464.
%K A094921 nonn
%O A094921 1,4
%A A094921 _N. J. A. Sloane_, Jun 18 2004