Number of subsets of {1..n} containing no differences or quotients of pairs of distinct elements.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =7a(5) =12a(6) =18a(7) =31a(8) =46a(9) =72a(10) =102a(11) =172a(12) =259a(13) =428a(14) =607a(15) =989a(16) =1329a(17) =2142a(18) =3117a(19) =4953a(20) =6956a(21) =11032a(22) =15321a(23) =23979a(24) =33380a(25) =48699a(26) =66849a(27) =104853a(28) =144712a(29) =220758