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 A131081 #24 Dec 10 2024 05:23:34
%S A131081 8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,
%T A131081 4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,
%U A131081 0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8,7,4,1,0,1,4,7,8
%N A131081 Periodic sequence (8, 7, 4, 1, 0, 1, 4, 7).
%C A131081 Fourth column of triangular array T defined in A131074.
%H A131081 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,-1,1).
%F A131081 a(1) = 8, a(2) = a(8) = 7, a(3) = a(7) = 4, a(4) = a(6) = 1, a(5) = 0; for n > 8, a(n) = a(n-8).
%F A131081 G.f.: (8-x-3*x^2-3*x^3+7*x^4)/((1-x)*(1+x^4)).
%t A131081 PadRight[{},120,{8,7,4,1,0,1,4,7}] (* _Harvey P. Dale_, May 20 2012 *)
%o A131081 (PARI) {m=105; for(n=1, m, r=(n-1)%8; print1(if(r==0, 8, if(r==1||r==7, 7, if(r==2||r==6, 4, if(r==4, 0, 1)))), ","))}
%o A131081 (Magma) m:=105; [ [8, 7, 4, 1, 0, 1, 4, 7][(n-1) mod 8 + 1]: n in [1..m] ];
%Y A131081 Cf. A131074, A131028.
%K A131081 nonn,easy,less
%O A131081 1,1
%A A131081 _Klaus Brockhaus_, following a suggestion of _Paul Curtz_, Jun 14 2007