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%I #11 Mar 31 2012 20:30:55
%S 1,2,5,9,15,23,32,43,55,70,86,103,122,143,166,190,215,243,273,304,336,
%T 371,406,443,482,523,566,611,656,704,753,803,855,910,966,1024,1083,
%U 1145,1207,1270,1336,1404,1474,1544,1616,1690,1766,1843,1922,2004
%N a(n) counts different values of i^2+j^2+k^2 <= n^2 or number of distances from the origin to all integer points inside a sphere of radius n.
%H T. D. Noe, <a href="/A047809/b047809.txt">Table of n, a(n) for n = 0..1000</a>
%F a(n) = number of b(i) <= n^2, b() = A000378.
%t Table[ Length@Union@Flatten@Table[ i^2+j^2+k^2, {i, 0, n}, {j, 0, Min[ i, Floor[ Sqrt[ n^2-i^2 ] ] ]}, {k, 0, Min[ j, Floor[ Sqrt[ n^2-i^2-j^2 ] ] ]} ], {n, 0, 64} ]
%Y Cf. A047808, A000378.
%K nonn,easy,nice
%O 0,2
%A _Wouter Meeussen_,_David W. Wilson_
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