Number of integer points (x, y, z, w) at distance <= 1/2 from 3-sphere of radius n.

Terms

a(0) =1a(1) =32a(2) =200a(3) =528a(4) =1280a(5) =2744a(6) =4272a(7) =6592a(8) =10144a(9) =15048a(10) =19824a(11) =25824a(12) =34744a(13) =43520a(14) =55184a(15) =64680a(16) =80864a(17) =99184a(18) =115616a(19) =135144a(20) =157344a(21) =185872a(22) =207304a(23) =239600a(24) =272960a(25) =310240a(26) =351096a(27) =385392a(28) =433040a(29) =485528