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 A070462 #15 Dec 18 2023 13:06:22
%S A070462 0,1,4,9,16,25,36,9,24,1,20,1,24,9,36,25,16,9,4,1,0,1,4,9,16,25,36,9,
%T A070462 24,1,20,1,24,9,36,25,16,9,4,1,0,1,4,9,16,25,36,9,24,1,20,1,24,9,36,
%U A070462 25,16,9,4,1,0,1,4,9,16,25,36,9,24,1,20,1,24,9,36,25,16,9,4,1,0,1,4,9,16
%N A070462 a(n) = n^2 mod 40.
%H A070462 G. C. Greubel, <a href="/A070462/b070462.txt">Table of n, a(n) for n = 0..1000</a>
%H A070462 <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).
%F A070462 a(n) = a(n-20). - _G. C. Greubel_, Mar 25 2016
%t A070462 Table[Mod[n^2,40],{n,0,200}] (* _Vladimir Joseph Stephan Orlovsky_, Apr 27 2011 *)
%t A070462 PowerMod[Range[0,90],2,40] (* _Harvey P. Dale_, Oct 20 2013 *)
%o A070462 (PARI) a(n)=n^2%40 \\ _Charles R Greathouse IV_, Apr 06 2016
%Y A070462 Cf. A070456, A070457.
%K A070462 nonn,easy
%O A070462 0,3
%A A070462 _N. J. A. Sloane_, May 12 2002