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 A304493 #11 Dec 02 2019 15:14:08
%S A304493 1,2,3,5,5,8,7,11,13,12,14,18,19,20,17,19,23,24,27,28,26,31,22,27,32,
%T A304493 34,35,37,42,46,46,45,40,40,45,40,44,48,49,55,52,56,60,65,57,64,70,72,
%U A304493 69,70,68,64,64,67,69,67,72,71,75,80,73,79,89,84,88,94,100,94,84,96,116,117,106,116,107,106
%N A304493 a(0) = 1; a(n) = a(n-a(floor(n/2))) + a(n-a(floor(n/4))).
%H A304493 Robert Israel, <a href="/A304493/b304493.txt">Table of n, a(n) for n = 0..10000</a>
%H A304493 Ilya Gutkovskiy, <a href="/A304493/a304493.jpg">Scatter plot of a(n) up to n=50000</a>
%H A304493 <a href="/index/Ho#Hofstadter">Index entries for Hofstadter-type sequences</a>
%p A304493 f:= proc(n) option remember;
%p A304493 procname(n-procname(floor(n/2)))+procname(n-procname(floor(n/4)))
%p A304493 end proc:
%p A304493 f(0):= 1;
%p A304493 map(f, [$0..100]); # _Robert Israel_, Dec 02 2019
%t A304493 a[n_] := a[n] = a[n - a[Floor[n/2]]] + a[n - a[Floor[n/4]]]; a[0] = 1; Table[a[n], {n, 0, 75}]
%Y A304493 Cf. A002265, A004526, A005185, A083662, A244477.
%K A304493 nonn,look
%O A304493 0,2
%A A304493 _Ilya Gutkovskiy_, May 13 2018