OFFSET
0,2
COMMENTS
Number of integer 4-tuples (x,y,z,u) satisfying |x|^3+|y|^3+|z|^3+|u|^3 <= n^3, -n <= x,y,z,u <= n.
An associated sequence with the number of 4-tuples satisfying x^2+y^2+z^2+u^2 <= n^3 starts 1, 9, 321, 3777, 20185, 77313, 230897,...
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Apr 24 2010
STATUS
approved