a(n)=a(a(n-4))+a(n-a(n-4)).

Terms

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