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A053594
Open 3-dimensional ball numbers (version 2): a(n) is the number of integer points (i,j,k) contained in an open ball of diameter n, centered at (1/2,0,0).
0
0, 0, 2, 10, 28, 60, 110, 174, 256, 368, 498, 682, 884, 1140, 1422, 1750, 2104, 2560, 3026, 3546, 4140, 4828, 5542, 6382, 7224, 8136, 9122, 10274, 11460, 12732, 14094, 15558, 17080, 18752, 20458, 22410, 24364, 26516, 28678, 31006, 33400
OFFSET
0,3
COMMENTS
a(n)/(n/2)^3 - > (4/3)*Pi.
CROSSREFS
Sequence in context: A057753 A060515 A109723 * A006331 A252591 A296849
KEYWORD
easy,nonn
AUTHOR
Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 19 2000
STATUS
approved