Number of nonempty subsets of {1, 2, ..., n} having pairwise coprime elements.

Terms

a(0) =1a(1) =3a(2) =7a(3) =11a(4) =23a(5) =27a(6) =55a(7) =71a(8) =103a(9) =115a(10) =231a(11) =247a(12) =495a(13) =543a(14) =615a(15) =727a(16) =1455a(17) =1519a(18) =3039a(19) =3231a(20) =3615a(21) =3871a(22) =7743a(23) =7999a(24) =11167a(25) =11903a(26) =14655a(27) =15487a(28) =30975a(29) =31231