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 A094918 #13 May 19 2020 19:13:02 %S A094918 0,0,1,0,1,4,1,0,4,4,1,4,1,4,13,0,1,4,1,0,13,4,1,16,21,4,13,12,1,4,1, %T A094918 0,13,4,23,4,1,4,13,0,1,28,1,40,31,4,1,16,15,24,13,40,1,40,33,32,13,4, %U A094918 1,40,1,4,13,0,56,34,1,40,13,54,1,40,1,4,28,40,37,52,1,0,40,4,1,28,36,4,13,24 %N A094918 a(n) = (3^n-1)/2 mod n. %H A094918 Antti Karttunen, <a href="/A094918/b094918.txt">Table of n, a(n) for n = 1..16384</a> %H A094918 Antti Karttunen, <a href="/A094918/a094918.txt">Data supplement: n, a(n) computed for n = 1..65537</a> %o A094918 (PARI) A094918(n) = lift(Mod((3^n-1)/2,n)); \\ _Antti Karttunen_, May 19 2020 %Y A094918 (k^n-1)/(k-1) mod n for k = 1, ..., 10 gives A082495, this sequence, A094919, A094920, A094921, A094922, A094923, A094924 and A095250. %Y A094918 Cf. A003462. %K A094918 nonn,look %O A094918 1,6 %A A094918 _N. J. A. Sloane_, Jun 18 2004