Number of 3's when n is written in base b for 2<=b<=n+1.

Terms

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