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%I #15 Aug 14 2021 15:39:44
%S 6,12,24,30,48,72,96,120,144,168,192,240,264,312,336,384,408,432,480,
%T 504,528,552,576,600,672,696,720,768,816,864,936,1008,1032,1056,1104,
%U 1200,1248,1296,1344,1440,1512,1584,1680,1704,1752,1848,1920,2016
%N Number of points (i,j,k) on the surface of a sphere around (0,0,0) with squared radius A071609(n).
%C a(n) is the number of lattice points on a sphere around (0,0,0) with r^2 = A071609(n).
%H Hugo Pfoertner, <a href="/A071611/b071611.txt">Table of n, a(n) for n = 1..189</a>
%F a(n) = A005875(A071609(n)). - _Daniel Suteu_, Aug 13 2021
%e A sphere with radius 1 has 6 lattice points on its surface, so a(1)=6. A sphere with r=sqrt(2) passes through 12 lattice points of the shape (1,1,0), so a(2)=12. A sphere with r=sqrt(5) passes through 24 lattice points with shape (2,1,0), so a(3)=24. A sphere with r=sqrt(9) passes through 6 lattice points of shape (3,0,0) and through 24 lattice points of shape (2,2,1), so a(4)=6+24=30.
%Y Cf. A005875, A071342-A071344, A071609, A071610.
%K nonn
%O 1,1
%A _Hugo Pfoertner_, May 25 2002
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