Number of Gaussian integers z = a + bi satisfying n-1 < |z| <= n.

Terms

a(0) =1a(1) =4a(2) =8a(3) =16a(4) =20a(5) =32a(6) =32a(7) =36a(8) =48a(9) =56a(10) =64a(11) =60a(12) =64a(13) =88a(14) =84a(15) =96a(16) =88a(17) =104a(18) =108a(19) =120a(20) =128a(21) =116a(22) =144a(23) =136a(24) =140a(25) =168a(26) =160a(27) =168a(28) =164a(29) =176