A053592 Open 3-dimensional ball numbers (version 1): a(n) is the number of integer points (i,j,k) contained in an open ball of diameter n, centered at (0,0,0).

0, 1, 1, 19, 27, 81, 93, 179, 251, 389, 485, 739, 895, 1189, 1365, 1791, 2103, 2553, 2969, 3695, 4139, 4945, 5497, 6403, 7123, 8217, 9093, 10395, 11459, 12893, 13997, 15515, 17071, 18853, 20377, 22575, 24303, 26745, 28545, 31103, 33371

Offset

0,4

Comments

a(n)/(n/2)^3 -> (4/3)*Pi.

Links

Table of n, a(n) for n=0..40.

Crossrefs

Sequence in context: A259054 A029510 A029537 * A146683 A146651 A146808

Adjacent sequences: A053589 A053590 A053591 * A053593 A053594 A053595

Keyword

easy,nonn

Author

Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 19 2000

Status

approved