Number of nondividing sets on {1,2,...,n}.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =7a(5) =11a(6) =14a(7) =21a(8) =27a(9) =38a(10) =52a(11) =73a(12) =90a(13) =123a(14) =159a(15) =211a(16) =263a(17) =344a(18) =413a(19) =535a(20) =658a(21) =832a(22) =1026a(23) =1276a(24) =1499a(25) =1846a(26) =2226a(27) =2708a(28) =3229a(29) =3912