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A053595
Open 3-dimensional ball numbers (version 3): a(n) is the number of integer points (i,j,k) contained in an open ball of diameter n, centered at (1/2,1/2,0).
0
0, 0, 4, 12, 36, 56, 112, 168, 268, 372, 536, 680, 888, 1132, 1452, 1740, 2160, 2544, 3048, 3556, 4196, 4812, 5552, 6304, 7248, 8116, 9220, 10280, 11512, 12656, 14108, 15564, 17164, 18800, 20664, 22368, 24436, 26412, 28692, 30984, 33536
OFFSET
0,3
COMMENTS
a(n)/(n/2)^3 -> (4/3)*Pi.
CROSSREFS
Sequence in context: A200541 A149318 A233181 * A300553 A062858 A095735
KEYWORD
easy,nonn
AUTHOR
Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 19 2000
STATUS
approved