Number of solutions to x^2 + x*y + y^2 <= n excluding (0,0).

Terms

a(0) =0a(1) =6a(2) =6a(3) =12a(4) =18a(5) =18a(6) =18a(7) =30a(8) =30a(9) =36a(10) =36a(11) =36a(12) =42a(13) =54a(14) =54a(15) =54a(16) =60a(17) =60a(18) =60a(19) =72a(20) =72a(21) =84a(22) =84a(23) =84a(24) =84a(25) =90a(26) =90a(27) =96a(28) =108a(29) =108