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 A152889 #19 Apr 07 2024 17:42:29 %S A152889 1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0, %T A152889 0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4, %U A152889 0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0,1,0,4,0,0 %N A152889 Periodic sequence [1,0,4,0,0] of period 5. %H A152889 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,1). %F A152889 a(n+5) = a(n) with a(0) = 1, a(2) = a(3) = a(4) = 0 and a(2) = 4. %F A152889 O.g.f: (1+4z^2)/(1-z^5). %F A152889 a(n) = 1-2/5*5^(1/2)*cos(2*n*Pi/5)+2/5*2^(1/2)*(5-5^(1/2))^(1/2)*sin(2*n*Pi/5) + 2/5*5^(1/2)*cos(4*n*Pi/5)-2/5*2^(1/2)*(5+5^(1/2))^(1/2)*sin(4*n*Pi/5). %Y A152889 Cf. A026048. %K A152889 easy,nonn %O A152889 0,3 %A A152889 _Richard Choulet_, Dec 14 2008 %E A152889 More terms from _Philippe Deléham_, Dec 29 2008