Numbers that are congruent to 0 or 1 (mod 3).

Terms

a(0) =0a(1) =1a(2) =3a(3) =4a(4) =6a(5) =7a(6) =9a(7) =10a(8) =12a(9) =13a(10) =15a(11) =16a(12) =18a(13) =19a(14) =21a(15) =22a(16) =24a(17) =25a(18) =27a(19) =28a(20) =30a(21) =31a(22) =33a(23) =34a(24) =36a(25) =37a(26) =39a(27) =40a(28) =42a(29) =43