Number of primes with n digits.

Terms

a(0) =0a(1) =4a(2) =21a(3) =143a(4) =1061a(5) =8363a(6) =68906a(7) =586081a(8) =5096876a(9) =45086079a(10) =404204977a(11) =3663002302a(12) =33489857205a(13) =308457624821