A228419 Count of the first 10^n primes which do not contain the digit 7.

1, 8, 67, 539, 5034, 45549, 416913, 3570781, 32517377, 294828478, 2681147149, 23720397369, 212156228217

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Formula

a(n) <= 9^n. - Charles R Greathouse IV, May 21 2014

Example

a(1) = 8 since there are 8 primes in the first 10 (through 29) that do not contain a 7.  Namely: 2, 3, 5, 11, 13, 19, 23, 29.

Mathematica

Table[Length[Select[Range[10^n], DigitCount[Prime[#], 10, 7] == 0 &]], {n, 0, 5}] (* Robert Price, Mar 23 2020 *)

Crossrefs

Cf. A231412, A228413-A228421, A097952, A091634-A091643.

Sequence in context: A343091 A037594 A037685 * A091645 A015574 A370028

Adjacent sequences: A228416 A228417 A228418 * A228420 A228421 A228422

Keyword

more,nonn,base,hard

Author

Robert Price, Nov 09 2013

Extensions

a(12) from Lucas A. Brown, Mar 19 2024

Status

approved