A228414 Count of the first 10^n primes which do not contain the digit 2.

0, 7, 77, 697, 6497, 55552, 512100, 4710641, 42205969, 341224891, 2787791578, 22971326749, 190650687957

Offset: 0

Author

Robert Price, Nov 09 2013

Keywords

• more
• nonn
• base
• hard

Examples

			a(1) = 7 since there are 7 primes less than 29 (the 10th prime) that do not contain a 2.  Namely: 3, 5, 7, 11, 13, 17, 19.
		

Crossrefs

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

Programs

Mathematica

Table[Length[Select[Range[10^n], DigitCount[Prime[#], 10, 2] == 0 &]], {n, 0, 5}] (* Robert Price, Mar 23 2020 *)

Formula

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

Extensions

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