Fully multiplicative with a(p) = [ (p+1)/2 ] for prime p.

Terms

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