a(n) = Sum_{i,j,k in Z and i^2 + j^2 + k^2 <= n} i^2 + j^2 + k^2.

Terms

a(0) =0a(1) =6a(2) =30a(3) =54a(4) =78a(5) =198a(6) =342a(7) =342a(8) =438a(9) =708a(10) =948a(11) =1212a(12) =1308a(13) =1620a(14) =2292a(15) =2292a(16) =2388a(17) =3204a(18) =3852a(19) =4308a(20) =4788a(21) =5796a(22) =6324a(23) =6324a(24) =6900a(25) =7650a(26) =9522a(27) =10386a(28) =10386a(29) =12474