A186649 - OEIS

A186649

Total number of positive integers below 10^n requiring 2 positive biquadrates in their representation as sum of biquadrates.

1, 5, 14, 43, 143, 460, 1467, 4613, 14629, 46341, 146545, 463344, 1465658, 4634967, 14657277, 46350371

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OFFSET

1,2

COMMENTS

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).

LINKS

Table of n, a(n) for n=1..16.

Eric Weisstein's World of Mathematics, Waring's Problem.

MAPLE

isbiquadrate:=proc(n) type(root(n, 4), posint); end:

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:

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;

CROSSREFS

Cf. A003336.

Sequence in context: A197607 A296829 A102434 * A120901 A222988 A349222

Adjacent sequences: A186646 A186647 A186648 * A186650 A186651 A186652

KEYWORD

nonn

AUTHOR

Martin Renner, Feb 25 2011

EXTENSIONS

a(6) from Martin Renner, Feb 26 2011

a(7)-a(16) from Lars Blomberg, May 08 2011

STATUS

approved