A231591 Total number of 2's digits in primes less than 10^n.

1, 3, 32, 391, 3906, 39572, 400626, 4047829, 40794211, 410514052, 4126066282, 41436122092, 415853103290, 4171375888398

Offset

1,2

Links

Table of n, a(n) for n=1..14.

Example

a(2)=3, since there are 3 2's in primes less than 100. Namely: 2, 23, 29.

Mathematica

Table[Count[IntegerDigits[Prime[Range[PrimePi[10^n - 1]]]], 2, 2], {n, 7}] (* Robert Price, Jun 16 2019 *)

Crossrefs

Cf. A231411, A231590-A231598, A119290, A119291-A119300.

Sequence in context: A091705 A137215 A300366 * A123336 A058479 A264334

Adjacent sequences: A231588 A231589 A231590 * A231592 A231593 A231594

Keyword

nonn,base,more

Author

Robert Price, Nov 11 2013

Extensions

a(14) from Giovanni Resta, Jul 20 2015

Status

approved