Number of subsets of {1..n} containing all of their integer products <= n.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =12a(5) =24a(6) =44a(7) =88a(8) =152a(9) =232a(10) =444a(11) =888a(12) =1576a(13) =3152a(14) =6136a(15) =11480a(16) =17112a(17) =34224a(18) =63504a(19) =127008a(20) =232352a(21) =442208a(22) =876944a(23) =1753888a(24) =3138848a(25) =4895328a(26) =9739152a(27) =18141840a(28) =34044720a(29) =68089440