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A053591
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Closed 3-dimensional ball numbers (version 1): a(n)= number of integer points (i,j,k) contained in a closed ball of diameter n, centered at (0,0,0).
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0
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1, 1, 7, 19, 33, 81, 123, 179, 257, 389, 515, 739, 925, 1189, 1419, 1791, 2109, 2553, 3071, 3695, 4169, 4945, 5575, 6403, 7153, 8217, 9171, 10395, 11513, 12893, 14147, 15515, 17077, 18853, 20479, 22575, 24405, 26745, 28671, 31103, 33401
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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COMMENTS
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a(n)/(n/2)^3->4/3*Pi
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LINKS
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 19 2000
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STATUS
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approved
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