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 A076824 #18 Jun 09 2025 13:12:20
%S A076824 1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,
%T A076824 3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,
%U A076824 5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3,1,1,3,5,3
%N A076824 Let a(1)=a(2)=1, a(n)=(2^ceiling(a(n-1)/2)+1)/a(n-2).
%H A076824 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 1).
%F A076824 5-periodic with period (1, 1, 3, 5, 3)
%t A076824 LinearRecurrence[{0, 0, 0, 0, 1},{1, 1, 3, 5, 3},105] (* _Ray Chandler_, Aug 25 2015 *)
%t A076824 nxt[{a_,b_}]:={b,(2^Ceiling[b/2]+1)/a}; NestList[nxt,{1,1},110][[;;,1]] (* or *) PadRight[{},120,{1,1,3,5,3}] (* _Harvey P. Dale_, Jun 09 2025 *)
%Y A076824 Cf. A076839.
%K A076824 nonn
%O A076824 1,3
%A A076824 _Benoit Cloitre_, Nov 24 2002