Number of semiprimes <= 2^prime(n).

Terms

a(0) =1a(1) =2a(2) =10a(3) =42a(4) =589a(5) =2186a(6) =30253a(7) =113307a(8) =1608668a(9) =88157689a(10) =336717854a(11) =19015826478a(12) =282528883551