Number of integer solutions to x^2 + 4 * y^2 = n.

Terms

a(0) =1a(1) =2a(2) =0a(3) =0a(4) =4a(5) =4a(6) =0a(7) =0a(8) =4a(9) =2a(10) =0a(11) =0a(12) =0a(13) =4a(14) =0a(15) =0a(16) =4a(17) =4a(18) =0a(19) =0a(20) =8a(21) =0a(22) =0a(23) =0a(24) =0a(25) =6a(26) =0a(27) =0a(28) =0a(29) =4