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 A193991 #11 Jan 21 2013 23:05:16
%S A193991 1,2,4,3,6,8,12,4,9,12,10,12,18,9,24,4,5,18,27,18,48,10,24,16,10,12,
%T A193991 15,9,5,48,13,6,40,5,72,27,16,18,72,24,14,36,10,15,54,48,5,16,30,20,
%U A193991 20,12,5,30,60,9,108,4,60,72,45,26,36,10,108,40,19,5,96
%N A193991 Number of zeros in the period of Fibonacci 3-step sequence A000073 mod n.
%H A193991 T. D. Noe, <a href="/A193991/b193991.txt">Table of n, a(n) for n = 1..1000</a>
%t A193991 n = 3; Table[a = Join[{1}, Table[0, {n - 1}]]; a = Mod[a, i]; a0 = a; k = 0; zeros = 0; While[k++; s = Mod[Plus @@ a, i]; a = RotateLeft[a]; If[s == 0, zeros++]; a[[n]] = s; a != a0]; zeros, {i, 100}]
%Y A193991 Cf. A046738.
%K A193991 nonn
%O A193991 1,2
%A A193991 _T. D. Noe_, Aug 18 2011