Log2*(n) (version 2): take log_2 of n this many times to get a number < 2.

Terms

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