Number of primes <= A005867(n).

Terms

a(0) =0a(1) =0a(2) =1a(3) =4a(4) =15a(5) =92a(6) =757a(7) =8899a(8) =125261a(9) =2232782a(10) =51902553a(11) =1327191561a(12) =41351244491