Duplicate of A007093.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =10a(7) =11a(8) =12a(9) =13a(10) =14a(11) =15a(12) =16a(13) =20a(14) =21a(15) =22a(16) =23a(17) =24a(18) =25a(19) =26a(20) =30a(21) =31a(22) =32a(23) =33a(24) =34a(25) =35a(26) =36a(27) =40a(28) =41a(29) =42