a(n) is the number of products P of distinct positive integers satisfying P <= n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =7a(6) =8a(7) =11a(8) =12a(9) =15a(10) =16a(11) =21a(12) =22a(13) =25a(14) =28a(15) =31a(16) =32a(17) =37a(18) =38a(19) =43a(20) =46a(21) =49a(22) =50a(23) =59a(24) =60a(25) =63a(26) =66a(27) =71a(28) =72a(29) =81