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 A335901 #16 Jul 08 2020 13:05:57 %S A335901 1,2,2,2,4,2,4,2,4,4,4,4,4,4,4,4,4,4,4,4,8,4,8,4,4,4,4,4,8,4,8,4,4,4, %T A335901 4,4,8,4,8,4,8,8,8,8,8,8,8,8,4,8,4,8,4,8,4,8,8,8,8,8,8,8,8,8,4,8,4,8, %U A335901 4,8,4,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8 %N A335901 a(n) = 2*a(floor((n-1)/a(n-1))) with a(1) = 1. %C A335901 Least k such that a(k) = 2^n are 1, 2, 5, 21, 169, 2705, ... (Conjecture: This sequence is A117261). %H A335901 Robert Israel, <a href="/A335901/b335901.txt">Table of n, a(n) for n = 1..10000</a> %p A335901 f:= proc(n) option remember; %p A335901 2*procname(floor((n-1)/procname(n-1))) end proc: %p A335901 f(1):= 1: %p A335901 map(f, [$1..105]); # _Robert Israel_, Jul 08 2020 %t A335901 a[1] = 1; a[n_] := a[n] = 2 * a[Floor[(n-1)/a[n-1]]]; Array[a, 100] (* _Amiram Eldar_, Jun 29 2020 *) %o A335901 (PARI) a=vector(10^3); a[1]=1; for(n=2, #a, a[n]=2*a[(n-1)\a[n-1]]); a %Y A335901 Cf. A130147, A132424, A130535, A283207, A288914, A335898. %K A335901 nonn,easy %O A335901 1,2 %A A335901 _Altug Alkan_, following a suggestion from _Andrew R. Booker_, Jun 29 2020