a(n)=a(a(n-1)-2)+a(n+2-a(n-1)).

Terms

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