OFFSET
0,2
LINKS
S. K. K. Choi, A. V. Kumchev and R. Osburn, On sums of three squares
FORMULA
For asymptotics see Choi et al.
In particular, lim_{n -> infinity} a(n)/n^2 = 8*Pi^4 / (21*zeta(3)). - Ant King, Mar 15 2013
MATHEMATICA
Prepend[SquaresR[3, #]^2 &/@Range[39], 1]//Accumulate (* Ant King, Mar 15 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 04 2010
STATUS
approved