a(n) = a(n-1)*2 - floor(sqrt(a(n-2))).

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =5a(5) =9a(6) =16a(7) =29a(8) =54a(9) =103a(10) =199a(11) =388a(12) =762a(13) =1505a(14) =2983a(15) =5928a(16) =11802a(17) =23528a(18) =46948a(19) =93743a(20) =187270a(21) =374234a(22) =748036a(23) =1495461a(24) =2990058a(25) =5978894a(26) =11956059a(27) =23909673a(28) =47815889a(29) =95626889