Number of ordered pairs of integers (x,y) with x^2+y^2 < n^2.

Terms

a(0) =0a(1) =1a(2) =9a(3) =25a(4) =45a(5) =69a(6) =109a(7) =145a(8) =193a(9) =249a(10) =305a(11) =373a(12) =437a(13) =517a(14) =609a(15) =697a(16) =793a(17) =889a(18) =1005a(19) =1125a(20) =1245a(21) =1369a(22) =1513a(23) =1649a(24) =1789a(25) =1941a(26) =2109a(27) =2285a(28) =2449a(29) =2617