First differences of A035253.

Terms

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