Number of subsets of {1,..,n} containing at least one prime.

Terms

a(0) =0a(1) =2a(2) =6a(3) =12a(4) =28a(5) =56a(6) =120a(7) =240a(8) =480a(9) =960a(10) =1984a(11) =3968a(12) =8064a(13) =16128a(14) =32256a(15) =64512a(16) =130048a(17) =260096a(18) =522240a(19) =1044480a(20) =2088960a(21) =4177920a(22) =8372224a(23) =16744448a(24) =33488896a(25) =66977792a(26) =133955584a(27) =267911168a(28) =536346624a(29) =1072693248