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 A070446 #25 Sep 10 2019 21:48:20
%S A070446 0,1,4,9,16,1,12,1,16,9,4,1,0,1,4,9,16,1,12,1,16,9,4,1,0,1,4,9,16,1,
%T A070446 12,1,16,9,4,1,0,1,4,9,16,1,12,1,16,9,4,1,0,1,4,9,16,1,12,1,16,9,4,1,
%U A070446 0,1,4,9,16,1,12,1,16,9,4,1,0,1,4,9,16,1,12,1,16,9,4,1,0,1,4,9,16,1,12,1
%N A070446 a(n) = n^2 mod 24.
%C A070446 Periodic with period = 12. - _Harvey P. Dale_, Jun 19 2014
%C A070446 From _Jesse Fiedler_, Aug 23 2019: (Start)
%C A070446 If a(n) = 1, then n is odd and is not divisible by 3.
%C A070446 For n <= 7919 and a(n)=1, approximately 37.8% of values of n are prime.
%C A070446 For n <= 104729, and a(n)=1, approximately 28.64% of values of n are prime.
%C A070446 (End)
%H A070446 G. C. Greubel, <a href="/A070446/b070446.txt">Table of n, a(n) for n = 0..1000</a>
%H A070446 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).
%t A070446 Table[Mod[n^2,24],{n,0,200}] (* _Vladimir Joseph Stephan Orlovsky_, Apr 23 2011 *)
%t A070446 PowerMod[Range[0,100],2,24] (* or *) PadRight[{},100,{0,1,4,9,16,1,12,1,16,9,4,1}] (* _Harvey P. Dale_, Jun 19 2014 *)
%o A070446 (PARI) a(n)=n^2%24 \\ _Charles R Greathouse IV_, Apr 06 2016
%K A070446 nonn,easy
%O A070446 0,3
%A A070446 _N. J. A. Sloane_, May 12 2002