Tersum n + 21.

Terms

a(0) =21a(1) =22a(2) =23a(3) =24a(4) =25a(5) =26a(6) =18a(7) =19a(8) =20a(9) =3a(10) =4a(11) =5a(12) =6a(13) =7a(14) =8a(15) =0a(16) =1a(17) =2a(18) =12a(19) =13a(20) =14a(21) =15a(22) =16a(23) =17a(24) =9a(25) =10a(26) =11a(27) =48a(28) =49a(29) =50