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 A186649 #17 Feb 16 2025 08:33:14 %S A186649 1,5,14,43,143,460,1467,4613,14629,46341,146545,463344,1465658, %T A186649 4634967,14657277,46350371 %N A186649 Total number of positive integers below 10^n requiring 2 positive biquadrates in their representation as sum of biquadrates. %C A186649 A114322(n) + a(n) + A186651(n) + A186653(n) + A186655(n) + A186657(n) + A186659(n) + A186661(n) + A186663(n) + A186665(n) + A186667(n) + A186669(n) + A186671(n) + A186673(n) + A186675(n) + A186677(n) + A186680(n) + A186682(n) + A186684(n) = A002283(n). %H A186649 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WaringsProblem.html">Waring's Problem</a>. %p A186649 isbiquadrate:=proc(n) type(root(n,4),posint); end: %p A186649 isA003336:=proc(n) local x,y4; if isbiquadrate(n) then false; else for x from 1 do y4:=n-x^4; if y4<x^4 then return false; elif isbiquadrate(y4) then return true; fi; od; fi; end: %p A186649 a:=proc(n) local i,k; i:=0; for k from 2 to 10^n-1 do if isA003336(k) then i:=i+1; fi; od: return(i); end: for n from 1 do print(a(n)); od; %Y A186649 Cf. A003336. %K A186649 nonn %O A186649 1,2 %A A186649 _Martin Renner_, Feb 25 2011 %E A186649 a(6) from _Martin Renner_, Feb 26 2011 %E A186649 a(7)-a(16) from _Lars Blomberg_, May 08 2011