Add n-1 to n-th term of 'n appears n times' sequence (A002024).

Terms

a(0) =1a(1) =3a(2) =4a(3) =6a(4) =7a(5) =8a(6) =10a(7) =11a(8) =12a(9) =13a(10) =15a(11) =16a(12) =17a(13) =18a(14) =19a(15) =21a(16) =22a(17) =23a(18) =24a(19) =25a(20) =26a(21) =28a(22) =29a(23) =30a(24) =31a(25) =32a(26) =33a(27) =34a(28) =36a(29) =37