a(n)=a(a(n-1)-4)+a(n+4-a(n-1)).

Terms

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