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 A131080 #21 Apr 18 2024 09:31:34
%S A131080 4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,
%T A131080 3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,
%U A131080 0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4,4,3,1,0,0,1,3,4
%N A131080 Periodic sequence (4, 4, 3, 1, 0, 0, 1, 3).
%C A131080 Third column of triangular array T defined in A131074.
%H A131080 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,-1,1).
%F A131080 a(n) = a(n-8).
%F A131080 G.f.: x*(4-x^2-2*x^3+3*x^4)/((1-x)*(1+x^4)).
%o A131080 (PARI) {m=105; for(n=1, m, r=(n-1)%8; print1(if(r<2, 4, if(r==2||r==7, 3, if(r==3||r==6, 1, 0))), ","))}
%o A131080 (Magma) m:=105; [ [4, 4, 3, 1, 0, 0, 1, 3][(n-1) mod 8 + 1]: n in [1..m] ];
%Y A131080 Cf. A131074, A131027.
%K A131080 nonn,easy,less
%O A131080 1,1
%A A131080 _Klaus Brockhaus_, following a suggestion of _Paul Curtz_, Jun 14 2007