0,1

a(1) = 5 because A006988(1) = prime(10^1) = 29 = 11101 (base 2) has five bits.

Cf. A006988 ((10^n)-th prime), A006880 (pi(10^n)), A007053 (pi(2^n)), A099260 (decimal digit lengths).

Sequence in context: A080792 A090050 A046462 this_sequence A103215 A037942 A008784

Adjacent sequences: A099258 A099259 A099260 this_sequence A099262 A099263 A099264

more,nonn

Rick L. Shepherd (rshepherd2(AT)hotmail.com), Oct 11 2004