Completely multiplicative with a(prime(k)) = floor( (prime(k+1)+1)/2 ) for k-th prime prime(k).

Terms

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