0,2

a(n) = 0 for n's of the form 4^i*(8*j+3), A055046. [From Zak Seidov, May 12 2010]

Zak Seidov, Table of n,a(n) for n=0..1000

G.f.: theta_3(q)^2*theta_3(q^5), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018

x^2+y^2+k*z^2: A005875, A014455, A034933, A169783.

Sequence in context: A253185 A028658 A241535 * A236929 A028642 A159796

Adjacent sequences: A169781 A169782 A169783 * A169785 A169786 A169787

nonn

N. J. A. Sloane, May 12 2010

approved