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Search: id:A071611
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| A071611 |
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Number of points (i,j,k) on the surface of a sphere around (0,0,0) with squared radius A071609(n). |
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+0
3
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| 6, 12, 24, 30, 48, 72, 96, 120, 144, 168, 192, 240, 264, 312, 336, 384, 408, 432, 480, 504, 528, 552, 576, 600, 672, 696, 720, 768, 816, 864, 936, 1008, 1032, 1056, 1104, 1200, 1248, 1296, 1344, 1440, 1512, 1584, 1680, 1704, 1752, 1848, 1920, 2016
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n) = number of lattice point on sphere around (0,0,0) with r^2=A071609(n).
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EXAMPLE
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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.
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PROGRAM
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(FORTRAN) See program given in A071609
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CROSSREFS
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Cf. A071342-A071344 A071609 A071610.
Adjacent sequences: A071608 A071609 A071610 this_sequence A071612 A071613 A071614
Sequence in context: A061822 A119840 A069171 this_sequence A119500 A110967 A000082
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KEYWORD
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nonn
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AUTHOR
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Hugo Pfoertner (hugo(AT)pfoertner.org), May 25 2002
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